JP2010189060A - Foamable styrene system resin particle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent blocking at the time of preliminary foaming, excellent fluidity of foamed particles, suppress peeling of a coated drug, good fusion, and no oil leakage.
SOLUTION: Expandable styrene resin particles obtained by impregnating styrene resin particles with a foaming agent, wherein the foamable styrene resin particles are coated with a composition on the surface of the resin particles. , Polyethylene glycol A having a molecular weight of less than 400 covering the surface of the resin particles, 0.003 to 0.04 parts by weight of fatty acid triglyceride with respect to 100 parts by weight of the resin particles, and 100 parts by weight of the resin particles 0.2 to 0.8 parts by weight of a fatty acid metal salt and polyethylene glycol B having a molecular weight of less than 400,
The polyethylene glycols A and B are contained in 0.02 to 0.08 parts by weight with respect to 100 parts by weight of the resin particles, and are coated in two portions.
[Selection figure] None

Description

  The expandable styrenic resin particles of the present invention have no stickiness of the particles, are easy to transfer, and have excellent strength and printing performance when used as a food container without peeling off the chemical coated on the piping. The present invention also relates to expandable styrene resin particles capable of suppressing the property of the contents contained in the container to permeate to the outside very well, pre-expanded particles using the same, and foamed articles thereof.

The foamable thermoplastic resin particles of the present invention are used as materials for various molded products. However, foods and drinks containing fat and oil components such as instant noodles, fried chicken, fat-containing foods, regular coffee, and particularly foamed molded products. It is preferable to use it as a foam molding material for containers such as curry having high permeability. In addition, it is also useful as a foam molding material for drain pans (receiving trays) and portable ice boxes used for home air conditioners and the like.
When the expandable styrenic resin particles are heated with water vapor, hot air, or the like, a large number of bubbles are generated in the particles and become pre-expanded particles. When the pre-expanded particles are filled in a mold having a desired shape and heated with steam, the pre-expanded particles are fused to each other to obtain a foamed molded product.
The foam obtained in this way is fused with each other to form the shape of the mold, but the particles are not completely integrated with each other. Is present. Therefore, for example, when the molded product is used as a container, when the content to be contained is particularly high in fats and oils, for example, in the content of oils and fats of 30% or more, the components of the content are the outer wall of the molded product or the molded product. There is a risk of penetrating into the inside of.

  Conventionally, expandable styrene resin particles for food containers and food containers using the same have been provided. That is, expandable styrene resin particles having a styrene monomer content of 1000 ppm or less, and 0.01 to 0.5 parts by weight of fatty acid amide or fatty acid bisamide are coated on 100 parts by weight of the resin particles. Expandable styrene resin particles for food containers (Patent Document 1). There is also provided an expandable styrenic resin particle for food containers, wherein 0.2 to 0.5 parts by weight of a fatty acid metal salt is further coated on the resin particle (Patent Document 1). Thereby, it is supposed that the penetration | invasion of the contents with strong osmosis | permeability, such as fats and oils, can be prevented substantially.

  In addition, expandable styrenic resin particles, pre-expanded particles using the same, and expanded molded articles are provided. That is, the expandable styrene resin particles containing a readily volatile foaming agent and having a styrene monomer content of 1000 ppm or less contain at least one kind of fatty acid amide or fatty acid bisamide with respect to 100 parts by weight of the resin particles. Foam coated with 0.01 parts by weight or more and 0.5 parts by weight or less and fatty acid metal salt 0.2 parts by weight or more and 1.0 parts by weight or less, and the amine value of fatty acid amide and fatty acid bisamide is 1 or less. Styrenic resin particles are provided (Patent Document 2). Thereby, it is supposed that the penetration of the content containing a large amount of oils and fats can be prevented, and mold contamination and mold corrosion can be prevented.

  In addition, expandable styrenic resin particles are provided. That is, it consists of styrene resin particles, impregnated with 3 to 10% by weight of a foaming agent, and 0.01 to 0.3% by weight of fatty acid triglyceride and a molecular weight of 400 to 5000 on the particle surface. These are expandable styrene resin particles coated with 0.001 to 0.1% by weight (Patent Document 3). Thereby, it is said that it fuse | melts well mutually and can shorten forming time, especially cooling time.

  Also provided are expandable thermoplastic resin particles and pre-expanded particles and expanded molded articles using the same. That is, it is an expandable thermoplastic resin particle formed by coating or containing a fluorine-containing block copolymer and a fusion accelerator (fatty acid triglyceride) (Patent Document 4). This prevents permeation of the oil and fat component and eliminates stickiness during transportation of the particles after preliminary foaming.

  There is also provided a coating composition for thermoplastic resin particles for molding a foam container. That is, with respect to the thermoplastic resin particles, a polyethylene glycol having a molecular weight in the range of 200 to 800 is contained in an amount greater than 0.01% by weight, and a polyolefin wax greater than 0.01% by weight, 0.01% by weight It is a container using thermoplastic resin particles coated with a metal salt of a higher fatty acid, polyethylene glycol having a molecular weight of about 900 to 10000, an amount greater than 0.01% by weight and a fatty acid bisamide greater than 0.01% by weight. . This is said to be less permeable to leakage and / or dirt caused by liquid and / or oily and fatty foods.

JP 2003-201360 A JP 2004-315806 A JP 11-228729 A Japanese Patent No. 3363378 JP 2006-518895 A JP 2003-82149 A

  However, if the above-described method is used, the particles capable of suppressing the permeation of fats and oils are sticky, and it takes time to transfer the particles. The drug coated on the surface accumulates in the form of cholesterol in the transfer pipe, and finally There was a problem of obstruction. Further, when the chemicals are peeled off, when used for the contents having an oil and fat content of 30% or more, the components of the contents may permeate into the outer wall of the molded body or the inside of the molded body.

In Patent Document 1 and Patent Document 2, 0.01 to 0.5 parts by weight of fatty acid amide or fatty acid bisamide is coated, and in the examples, 0.1 parts by weight of polyethylene glycol is coated on all.
However, if fatty acid amide is used in a large amount, blocking during pre-foaming often occurs and the efficiency of the product is lowered, which is not preferable in terms of cost. Further, when polyethylene glycol is used in a large amount, the fluidity of the pre-foamed particles is lowered, and there is a case where a defective molded body is obtained due to poor filling.
Patent Document 3 proposes a method in which fatty acid triglyceride is coated on the particle surface of a thermoplastic resin as a fusion accelerator on the particle surface. However, it does not describe preventing permeation of fats and oils contained in the container.
Patent Document 4 proposes a method in which a fluoropolymer and a fatty acid triglyceride are coated or contained in a thermoplastic resin. If a fluorine-based polymer is used, it is possible to suppress the permeation of fats and oils. However, such a fluorine-based polymer is very expensive and is not costly.
Patent Document 5 uses a molecular weight of 400 of liquid polyethylene glycol in Examples. However, when polyethylene glycol having a molecular weight of 400 was used, the powder coating agent was peeled off when the beads were transported, and the leakage prevention of oil and fat components was insufficient.
In Patent Document 6, the composition of pentane in the examples is isopentane: normal pentane = 30: 70 to 70:30 in weight ratio. However, in this case, leakage prevention of the oil and fat component was insufficient.

  The object of the present invention is to solve all the above-mentioned problems. There is no blocking at the time of preliminary foaming, the fluidity of the foamed particles is excellent, the peeling of the coated drug is suppressed, the fusion is good, and the oil leaks. The present invention provides an expandable styrenic resin particle free from the above.

The inventors of the present invention have intensively studied to solve the above problems,
Expandable styrene resin particles obtained by impregnating a styrene resin particle with a foaming agent, and the expandable styrene resin particles have the resin particle surface coated with a composition,
The composition includes polyethylene glycol A covering the surface of the resin particles, 0.003 to 0.04 parts by weight of fatty acid triglyceride with respect to 100 parts by weight of the resin particles, and 0 with respect to 100 parts by weight of the resin particles. 2 to 0.8 parts by weight of a fatty acid metal salt and polyethylene glycol B,
The polyethylene glycols A and B contain 0.02 to 0.08 parts by weight with respect to 100 parts by weight of the resin particles, and are coated in two portions.
The polyethylene glycol A is a polyethylene glycol having a molecular weight of less than 400,
The polyethylene glycol B is an expandable styrene resin particle having a molecular weight of less than 400.

  As a result, there is no blocking during pre-foaming, excellent fluidity of the foamed particles, little peeling of the coated drug, good fusion, no oil leakage, and further coating with polyethylene glycol in two portions Thus, when the resin is transferred, the drug coated on the surface is difficult to peel off, and the spreading effect of the drug can be improved.

It is the schematic which shows the suction conveyance apparatus of an expandable polystyrene resin particle.

Hereinafter, embodiments of the present invention will be described in more detail.
(Styrene resin particles)
The styrenic resin particles in the present invention are generally known styrene resin granules, and are mainly composed of styrene. Even in the case of a styrene homopolymer, α-methylstyrene, paramethylstyrene, t- Styrene derivatives such as butylstyrene and chlorostyrene, acrylic acid and methacrylic acid esters such as methyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, cetyl methacrylate, and various monomers such as dimethyl fumarate and ethyl fumarate Copolymers of Moreover, you may use together polyfunctional monomers, such as divinylbenzene and alkylene glycol dimethacrylate. A weight average molecular weight of 150,000 to 400,000, preferably 250,000 to 350,000, which is generally usable as expanded polystyrene can be used.

  Moreover, it is preferable that the particle diameter of the expandable styrene resin particle in this invention exists in 200-600 micrometers. If it is less than 200 μm, the dissipation rate of the volatile foaming agent is too fast and the bead life is shortened. . As a method for obtaining particles of 200 to 600 μm, particles obtained by a normal suspension polymerization method may be classified, or the aforementioned suspension seed polymerization method may be used. It is preferable to use a suspension seed polymerization method because a higher yield can be obtained.

(Volatile foaming agent)
Examples of the readily volatile blowing agent used in the present invention include aliphatic hydrocarbons such as propane, normal butane, isobutane, normal pentane, isopentane, neopentane, and normal hexane, and alicyclic hydrocarbons such as cyclobutane, cyclopentane, and cyclohexane. These may be used, but these may be used alone or in combination of two or more. The usage-amount of the easily volatile foaming agent in this invention is 3 to 6 weight%. Preferably it is 3.3 to 5 weight%, More preferably, it is 3.8 to 4.5 weight%. If it is less than 3% by weight, the fusion rate during molding tends to decrease, which is not preferred. If it exceeds 6% by weight, the particle gap of the molded product tends to increase, and the surface beauty tends to be impaired. Since the cycle becomes long, it is not preferable. These foaming agents may be added during the polymerization process of the expandable styrene resin particles, or may be added after the polymerization process is completed.
Further, propane is preferably contained in an amount of 0.01 to 1% by weight. More preferably, the content is 0.03 to 0.8% by weight. If the amount is less than 0.01% by weight, the particle gap of the molded body tends to increase and the surface beauty tends to be impaired.
Moreover, about the composition of pentane, the ratio of isopentane is 10 weight%-less than 30 weight% by weight ratio. If it is less than 10% by weight, the particle gap of the molded body tends to increase and the surface beauty tends to be impaired, and if it is 30% by weight or more, the leakage prevention of oil and fat components becomes insufficient.

（Ｒは飽和もしくは不飽和の脂肪族炭化水素基） (Fatty acid triglyceride)
In the present invention, a fatty acid triglyceride represented by the following general formula 1 is used.

(R is a saturated or unsaturated aliphatic hydrocarbon group)

  Examples of fatty acid triglycerides include caprylic acid triglyceride, capric acid triglyceride, lauric acid triglyceride, myristic acid triglyceride, palmitic acid triglyceride, stearic acid triglyceride, arachidic acid triglyceride, behenic acid triglyceride, lignoceric acid triglyceride, 12-hydroxystearic acid triglyceride, Examples include methylol stearic acid triglyceride, methylol behenic acid triglyceride, oleic acid triglyceride, erucic acid triglyceride, and ricinoleic acid triglyceride.

  The carbon number of the saturated or unsaturated hydrocarbon group R represented by the general formula 1 is preferably 7 to 23, more preferably 15 to 21, and particularly preferably 17 (stearic acid). Of the triglycerides described above, it is preferable to use 12-hydroxystearic acid triglyceride, and among them, it is most preferable to use 12-hydroxystearic acid triglyceride alone.

  The amount of fatty acid triglyceride used in the present invention is 0.003 to 0.04 parts by weight, preferably 0.003 to 0.009 parts by weight, and more preferably 0.003 parts by weight with respect to 100 parts by weight of expandable styrene resin particles. 003 to 0.006 parts by weight. When the amount is less than 0.003 parts by weight, the effect of promoting fusion between particles is thin and the molding cycle becomes long, which is not preferable. When the amount exceeds 0.04 parts by weight, a large amount of blocking occurs during pre-foaming, and the filling property of the pre-foamed particles into the molding machine mold deteriorates.

(Fatty acid metal salt)
Examples of the fatty acid metal salt include zinc stearate, calcium stearate, magnesium stearate, aluminum stearate, zinc laurate, and calcium laurate. Among these, zinc stearate is preferably used. Normally, the fatty acid constituting the commercially available zinc stearate is a mixture of stearic acid as a main component and palmitic acid, myristic acid, lauric acid, arachidic acid, behenic acid, etc., and zinc stearate in the present invention Also, such a commercial product can be used.

  As for zinc stearate, an aggregate in which a plurality of particles are aggregated is used. The average maximum length of the aggregate is 0.5 to 30 μm, and when it is larger than 30 μm, the aggregate is unevenly distributed on the surface of the expandable styrenic resin particles and is likely to be coated. Therefore, it is not preferable. On the other hand, if it is smaller than 0.5 μm, a large amount of fatty acid metal salts that are not aggregated are likely to be present, and as a result, the leakage prevention effect is lowered, which is not preferable.

  The amount of zinc stearate used is preferably 0.2 to 0.8 parts by weight, more preferably 0.3 to 0.7 parts by weight, with respect to 100 parts by weight of expandable styrene resin particles, and 0.5 to 0.7 part by weight is particularly preferred. If the amount is less than 0.2 parts by weight, the effect of preventing the penetration of food container contents such as fats and oils becomes small. When the amount exceeds 0.8 parts by weight, peeling of the coated drug during particle transfer increases, or fusion during molding deteriorates.

(Polyethylene glycol)
In the present invention, a spreading effect is imparted by using polyethylene glycol, which is generally used as an antistatic agent, twice.

  Polyethylene glycol is contained in an amount of 0.02 to 0.08 parts by weight based on 100 parts by weight of the resin particles, and is coated in two portions. That is, the amount of polyethylene glycol used is preferably 0.01 to 0.04 parts by weight, preferably 0.02 to 0.04 parts by weight for the first coating (polyethylene glycol A) with respect to 100 parts by weight of expandable styrene resin particles. Part by weight is more preferred. If the amount is less than 0.01 parts by weight, the antistatic effect is low and there is a risk of ignition due to static electricity during use. If the amount is more than 0.04 parts by weight, the coating of powders such as fatty acid metal salts becomes uneven due to stickiness of the particles. . The second coating (polyethylene glycol B) is preferably from 0.01 to 0.04 parts by weight, more preferably from 0.02 to 0.04 parts by weight, based on 100 parts by weight of the expandable styrene resin particles. If it is less than 0.01, the spreading effect is weak, and a large amount of the coated drug is peeled off during transport. When the amount is more than 0.04 parts by weight, the particles are sticky and the coated drug is largely peeled off during transport.

  In addition, it is preferable that the molecular weight of polyethylene glycol used is less than 400 (less than 400). More preferably, it is 150-400. 200 to 300 is more preferable. When the molecular weight is smaller than 150 (less than 150), the adhesion effect is weak, and a large amount of the coated drug is peeled off during transport. When it is larger than 400 (400 or more), the viscosity becomes high, the particles are sticky, the fluidity is inferior, and a large amount of the coated drug is peeled off during transport.

The molecular weight of polyethylene glycol is determined by the following method. The hydroxyl value based on JIS K0070 was determined, and the average molecular weight of polyethylene glycol was calculated according to Formula 1.
Formula 1: Average molecular weight of polyethylene glycol = 56106 / hydroxyl value × 2
56106: Coefficient by molecular weight of potassium hydroxide

The first coating with polyethylene glycol (polyethylene glycol A) may be mixed for a certain time in a mixer such as a Henschel mixer or sprayed in a line from immediately after dehydration to the mixer. Then, fatty acid triglyceride is mixed and coated. When fatty acid triglyceride and fatty acid metal salt are used in combination, they may be mixed and coated separately or separately. Finally, the second coating with polyethylene glycol (polyethylene glycol B) is preferably mixed and coated for a certain period of time in a mixer such as a known Henschel mixer.
That is, it is characterized in that polyethylene glycol or the like is coated twice, and after the first coating such as polyethylene glycol, fatty acid triglyceride or fatty acid metal salt is added and coated, and then the second coating such as polyethylene glycol is performed. This is a method for producing expandable styrene resin particles.

(Pre-foaming method for expandable styrene resin particles)
As the pre-foaming method for the expandable styrene resin particles in the present invention, a conventionally known method can be used. For example, pre-expanded particles can be obtained by heating with water vapor in a rotary stirring pre-foaming device. Moreover, the obtained pre-expanded particles are filled in a mold having a desired shape and heated with water vapor or the like to obtain a foam-molded product.

(Molding)
The food container obtained by pre-foaming and molding the expandable styrenic resin particles for food containers of the present invention can substantially suppress the penetration of contents having strong osmotic power such as fats and oils. Therefore, it can be used for instant noodles, curry, stew, mayonnaise, margarine, donut, hamburger, fried chicken, coffee and the like.

  Hereinafter, although an example and a comparative example explain the present invention, the present invention is not limited to this.

Example 1
40 kg of ion-exchanged water is supplied into a 100 liter stainless steel autoclave equipped with a stirrer, and 40 kg of styrene monomer and tricalcium phosphate (manufactured by Boudenheim) are stirred into the ion-exchanged water. 40 g of trade name “C13-09”), 0.5 g of potassium persulfate, 140 g of benzoyl peroxide having a purity of 75% by weight and 30 g of t-butylperoxybenzoate were prepared to prepare a suspension.

  Next, the suspension was heated to 90 ° C. over 1 hour while stirring at a stirring speed of 200 RPM, and the suspension was held at 90 ° C. for 6 hours for polymerization. After adding 40 g of tricalcium phosphate and 0.4 g of α-olefin sulfonate (product name “Lipolane PJ-400” manufactured by Lion Corporation), 1600 g of n-pentane and 400 g of i-pentane were press-fitted to obtain a suspension. The temperature was raised to 130 ° C. over 40 minutes and left at 130 ° C. for 3 hours.

  Thereafter, the suspension was cooled, and 35% hydrochloric acid was added until the pH of the suspension was 2, to decompose tricalcium phosphate. Subsequently, the suspension was washed with water for 10 minutes with a dehydrator, dehydrated, and then air-dried to obtain expandable polystyrene resin particles.

  The obtained expandable polystyrene resin particles were sieved with a sieve having an opening defined by JIS of 0.600 mm, and the expandable polystyrene resin particles that passed through the sieve were collected. Next, the collected expandable polystyrene resin particles are sieved with a sieve having an opening defined by JIS of 0.300 mm, and the expandable polystyrene resin particles remaining on the sieve are collected, whereby the median diameter of the particles is reduced. 0.45 mm expandable polystyrene resin particles were obtained.

  8 kg (100 parts by weight) of the expandable polystyrene resin particles were put into a super mixer (internal volume 20 liters), and further polyethylene glycol A (made by NOF Corporation) shown in Table 1 with respect to 100 parts by weight of the expandable polystyrene resin particles. 0.02 part by weight of a trade name “PEG-300”, molecular weight 300) was added and stirred for 3 minutes. Thereafter, 0.50 parts by weight of zinc stearate shown in Table 1 (trade name “Zinc stearate GF-200” manufactured by NOF Corporation), 12-hydroxystearic acid triglyceride shown in Table 1 (trade name “K3 made by Kawaken Fine Chemicals) 0.02 part by weight of wax 500 ") was added sequentially, and the mixture was stirred at a blade rotation speed of 740 RPM for 3 minutes, and then again polyethylene glycol B (trade name" PEG-300 ", molecular weight 300, manufactured by NOF Corporation) shown in Table 1 0.02 part by weight was stirred for 3 minutes to obtain coated expandable polystyrene resin particles. The results are shown in Table 1.

  In each of the expandable polystyrene particles whose entire surface is coated on the skin layer, the weight ratio of expandable polystyrene particles, 12 hydroxystearic acid triglyceride, polyethylene glycol and zinc stearate is the expandable polystyrene particles in the super mixer, The weight ratio was the same as that of polyethylene glycol, 12-hydroxystearic acid triglyceride and zinc stearate.

(Example 2)
The same procedure as in Example 1 was performed except that stearic acid triglyceride (trade name “Riquemar VT50” manufactured by Riken Vitamin Co., Ltd.) was used instead of 12-hydroxystearic acid triglyceride (trade name “K3 Wax 500” manufactured by Kawaken Fine Chemicals).
(Example 3)
Instead of 0.02 part by weight of 12-hydroxystearic acid triglyceride (trade name “K3 Wax 500” manufactured by Kawaken Fine Chemical Co., Ltd.), 0.02 parts by weight of 12-hydroxystearic acid triglyceride (trade name “K3 Wax 500” manufactured by Kawaken Fine Chemical Co., Ltd.). 005 parts by weight, polyethylene glycol A (Nippon Yushi Co., Ltd., trade name “PEG-300”, molecular weight 300) instead of 0.02 parts by weight, polyethylene glycol A (Nippon Yushi Co., Ltd., trade name “PEG-300”, molecular weight 300) 0.01 parts by weight, polyethylene glycol B (trade name “PEG-300” manufactured by NOF Corporation, molecular weight 300) instead of 0.02 part by weight, polyethylene glycol B (trade name “PEG-300” manufactured by NOF Corporation), Similar to Example 1 except that the molecular weight was 300) 0.03 part by weight. Subjecting was.

Example 4
Instead of 0.02 part by weight of 12-hydroxystearic acid triglyceride (trade name “K3 Wax 500” manufactured by Kawaken Fine Chemical Co., Ltd.), 0.02 parts by weight of 12-hydroxystearic acid triglyceride (trade name “K3 Wax 500” manufactured by Kawaken Fine Chemical Co., Ltd.). 04 parts by weight, polyethylene glycol A (Nippon Yushi Co., Ltd., trade name “PEG-300”, molecular weight 300) instead of 0.02 parts by weight, polyethylene glycol A (Nippon Yushi Co., Ltd., trade name “PEG-300”, molecular weight 300) ) 0.03 parts by weight, polyethylene glycol B (Nippon Yushi Co., Ltd., trade name “PEG-300”, molecular weight 300) instead of 0.02 parts by weight, polyethylene glycol B (Nippon Yushi Co., Ltd., trade name “PEG-300”) , Molecular weight 300) The same as in Example 1 except for 0.01 parts by weight Subjecting was.

(Example 5)
Zinc stearate (trade name “Zinc stearate GF-200” manufactured by Nippon Oil & Fats Co., Ltd.) 0.20 weight instead of 0.50 parts by weight Polyethylene glycol A (Nippon Yushi Co., Ltd., trade name “PEG-300”, molecular weight 300) instead of 0.02 part by weight, polyethylene glycol A (Nippon Yushi Co., Ltd., trade name “PEG-300”, molecular weight 300). 0.03 part by weight, polyethylene glycol B (trade name “PEG-300” manufactured by NOF Corporation, molecular weight 300) polyethylene glycol B (trade name “PEG-300” manufactured by NOF Corporation), molecular weight instead of 0.02 part by weight 300) It carried out like Example 1 except having set it as 0.03 weight part.

(Example 6)
Zinc stearate (trade name “Zinc stearate GF-200” manufactured by Nippon Oil & Fats Co., Ltd.) 0.80 wt. Example 1 was carried out in the same manner as in Example 1 except that the part was changed.

(Example 7)
In place of 0.02 part by weight of polyethylene glycol A (trade name “PEG-300”, molecular weight 300 manufactured by NOF Corporation), 0.02 part by weight of polyethylene glycol A (trade name “PEG-300”, molecular weight 300 manufactured by NOF Corporation) 03 parts by weight,
Polyethylene glycol B (Nippon Yushi Co., Ltd., trade name “PEG-300”, molecular weight 300) 0.02 parts by weight Polyethylene glycol B (Nippon Yushi Co., Ltd., trade name “PEG-300”, molecular weight 300) 0.04 wt. Example 1 was carried out in the same manner as in Example 1 except that the part was changed.

(Example 8)
The same procedure as in Example 1 was carried out except that polyethylene glycol having a molecular weight of 200 ("PEG200" manufactured by NOF Corporation) was used for polyethylene glycol A and polyethylene glycol B instead of polyethylene glycol having a molecular weight of 300.

Example 9
It implemented like Example 1 except having used propane 400g, n-pentane 1600g, and i-pentane 400g as a volatile foaming agent.

(Comparative Example 1)
Instead of 0.02 part by weight of 12-hydroxystearic acid triglyceride (trade name “K3 Wax 500” manufactured by Kawaken Fine Chemical Co., Ltd.), 0.02 parts by weight of 12-hydroxystearic acid triglyceride (trade name “K3 Wax 500” manufactured by Kawaken Fine Chemical Co., Ltd.). The same operation as in Example 1 was carried out except that the content was changed to 001 parts by weight.

(Comparative Example 2)
Instead of 0.02 part by weight of 12-hydroxystearic acid triglyceride (trade name “K3 Wax 500” manufactured by Kawaken Fine Chemical Co., Ltd.), 0.02 parts by weight of 12-hydroxystearic acid triglyceride (trade name “K3 Wax 500” manufactured by Kawaken Fine Chemical Co., Ltd.). The same operation as in Example 1 was carried out except that the amount was changed to 05 parts by weight.

(Comparative Example 3)
Zinc stearate (trade name “Zinc stearate GF-200” manufactured by Nippon Oil & Fats Co., Ltd.) 1.00 wt. Example 1 was carried out in the same manner as in Example 1 except that the part was changed.

(Comparative Example 4)
Zinc stearate (trade name “Zinc stearate GF-200” manufactured by Nippon Oil & Fats Co., Ltd.) 0.50 parts by weight Zinc stearate (trade name “Zinc stearate GF-200” manufactured by Nippon Oil & Fats Co., Ltd.) 0.10 wt. Example 1 was carried out in the same manner as in Example 1 except that the part was changed.

(Comparative Example 5)
In place of 0.02 part by weight of polyethylene glycol A (trade name “PEG-300”, molecular weight 300 manufactured by NOF Corporation), 0.02 part by weight of polyethylene glycol A (trade name “PEG-300”, molecular weight 300 manufactured by NOF Corporation) 005 parts by weight, polyethylene glycol B (Nippon Yushi Co., Ltd., trade name “PEG-300”, molecular weight 300) instead of 0.02 parts by weight, polyethylene glycol B (Nippon Yushi Co., Ltd., trade name “PEG-300”, molecular weight 300) The same operation as in Example 1 was carried out except that the amount was 0.005 part by weight.

(Comparative Example 6)
In place of 0.02 part by weight of polyethylene glycol A (trade name “PEG-300”, molecular weight 300 manufactured by NOF Corporation), 0.02 part by weight of polyethylene glycol A (trade name “PEG-300”, molecular weight 300 manufactured by NOF Corporation) 1 part by weight, polyethylene glycol B (Nippon Yushi Co., Ltd., trade name “PEG-300”, molecular weight 300) instead of 0.02 part by weight, polyethylene glycol B (Nippon Yushi Co., Ltd., trade name “PEG-300”, molecular weight 300) The same operation as in Example 1 was carried out except that the amount was 0.1 parts by weight.

(Comparative Example 7)
Other than using polyethylene glycol A having a molecular weight of 400 (“PEG400” manufactured by NOF Corporation) instead of polyethylene glycol A having a molecular weight of 300, and polyethylene glycol having a molecular weight of 400 (“PEG400” manufactured by NOF Corporation) instead of polyethylene glycol B having a molecular weight of 300. Was carried out in the same manner as in Example 1.

(Comparative Example 8)
Example 1 was performed in the same manner as in Example 1 except that polyethylene glycol having a molecular weight of 800 (“PEG 800” manufactured by NOF Corporation) was used as polyethylene glycol A and polyethylene glycol B instead of polyethylene glycol having a molecular weight of 300.

(Comparative Example 9)
The same as in Example 1 except that polyethylene glycol is not used for polyethylene glycol A, but 0.1 part by weight is used only for polyethylene glycol B (trade name “PEG-300”, molecular weight 300, manufactured by NOF Corporation). went.

(Comparative Example 10)
The same as in Example 1 except that polyethylene glycol is not used for polyethylene glycol B but only 0.1 part by weight is used for polyethylene glycol A (trade name “PEG-300”, molecular weight 300, manufactured by NOF Corporation). went.

(Comparative Example 11)
12-hydroxystearic acid triglyceride (trade name “K3 wax 500” manufactured by Kawaken Fine Chemical Co., Ltd.) 0.2 parts by weight instead of 0.02 part by weight stearic acid triglyceride (trade name “Riquemar VT50” manufactured by Riken Vitamin Co., Ltd.), stearic acid Zinc stearate (trade name “Zinc stearate GF-200” manufactured by NOF Corporation) instead of 0.50 parts by weight of zinc (trade name “Zinc stearate GF-200” manufactured by NOF Corporation), 0.40 parts by weight, The same procedure as in Example 1 was performed except that polyethylene glycol B having a molecular weight of 400 (“PEG400” manufactured by NOF Corporation) was used instead of polyethylene glycol A having a molecular weight of 300, and polyethylene glycol B was not used.

(Comparative Example 12)
Polypropylene glycol A (trade name “polypropylene glycol 1000”, molecular weight 1000, manufactured by Pure Chemical Co., Ltd.), polyethylene glycol B (manufactured by NOF Corporation) instead of polyethylene glycol A (trade name “PEG-300”, molecular weight 300, manufactured by NOF Corporation) The same procedure as in Example 1 was performed except that polypropylene glycol B (trade name “polypropylene glycol 1000”, molecular weight 1000, manufactured by Junsei Chemical Co., Ltd.) was used instead of the trade name “PEG-300”, molecular weight 300). In the table, * 1) indicates these points, and * 2) indicates the blending amount of polypropylene glycol A + B. The molecular weight was measured by the same method as that measured with polyethylene glycol.

(Comparative Example 13)
It implemented like Example 1 except having used propane 400g, n-pentane 1900g, and i-pentane 100g as a volatile foaming agent.

(Comparative Example 14)
The same procedure as in Example 1 was performed except that 400 g of propane, 1300 g of n-pentane, and 700 g of i-pentane were used as volatile blowing agents.

Next, various evaluation was performed about the Example and the comparative example. Table 1 shows the results.
<Suction transportation of expandable polystyrene resin particles>
The suction transport of expandable polystyrene resin particles was evaluated using a suction transport device ML-5500CB manufactured by MEL Engineering.
FIG. 1 is a schematic diagram showing a suction transport device ML-5500CB manufactured by MEL Engineering. In FIG. 1, 1 is a hopper, 2 is a suction part provided in the upper part. The hopper 1 is provided with a discharge pipe 11. Reference numeral 5 denotes a blower that sucks from the suction portion 11 by suction air through the suction tube 3 and through the bag filter 4. Reference numeral 6 denotes a drum provided directly below the discharge pipe 11. Reference numeral 7 denotes a flow pipe made of a polypropylene hose having an inner diameter of 50 mm and a length of 10 m. One of the flow pipes 7 is attached to the suction part 2, and the other is sucked and transported by the covered expandable polystyrene resin particles AB in the drum 6 via the suction nozzle 71.
Accordingly, as shown in FIG. 1, the flow pipe 7 is connected as vertically as possible, and the suction nozzle 71 is connected to the other end of the flow pipe 7. Here, the suction nozzle 71, that is, the suction nozzle is connected. From the above, each coated expandable polystyrene resin particle AB was sucked and transported. Thereafter, 8 m of expandable polystyrene resin particles AB were dropped from the hopper 1 and received by the drum 6. This suction transportation was repeated 12 times to obtain a foamed polystyrene resin particle which had been transported.

《Pre-foaming, cup molding》
The foamed polystyrene resin particles that have been transported are put into a batch type pre-foaming machine with a built-in rotor, and heated uniformly with water vapor so as to be foamed to a bulk density of 0.1 g / ml. Got.
The amount of the pre-foamed particles is determined by measuring the weight of the pre-foamed pre-foamed particles passed through a 10 mesh (1.7 mm) net and the weight of the pre-foamed particles remaining on the net before passing through the net. It was obtained by dividing by the weight of the expanded particles.
The obtained pre-expanded particles were aged and dried in the atmosphere for 12 hours. Next, pre-expanded particles are filled into a mold for forming a cup, heated with 0.22 MPa (gauge pressure) of water vapor for 6 seconds and then cooled, and the lip portion has a diameter of 95 mm, the bottom portion has a diameter of 68 mm, a height of 105 mm, an internal volume of 400 ml, A cup molded product having a wall thickness of about 2 mm was obtained.

<Oil exudation test>
After preparing 5 cup-shaped products obtained and supplying 100 g of seasoning and curry containing curry powder, which are used for instant noodles, the cup-shaped product is almost covered with a wrap film made of polyvinylidene chloride. The entire package was packaged to be hermetically sealed. Next, this cup-shaped article was left in an oven maintained at 60 ° C. for 24 hours.
After 24 hours, the cup-molded product was taken out of the oven, and the seepage of the yellow pigment by the curry powder on the side wall was visually observed. In the case of bleeding, the entire outer surface of the side wall of the cup molded product was copied onto paper, and the yellow pigment portion that was oozed out of the outer surface of the side wall of the cup molded product was copied onto the paper. The percentage of the weight of the paper corresponding to the entire side wall portion of the copied cup molded product is W1, and the weight of the paper corresponding to the copied yellow pigment portion W2 is calculated by the following formula, and the oil content of the five cup molded products is calculated. The maximum exudation value was evaluated according to the following criteria. In addition, the value of oil oozing property was described in parentheses in Table 1 evaluated according to the following criteria.
Oil exudation (%) = 100 × W2 / W1
○ ... Yellow pigment exuded, but oil exudability was less than 1%.
X: The oil leaching property was 1% or more.
If it exceeds 1% in this oil leaching test, when stored at room temperature for a long time, the oil content of the contents may ooze out and the commercial value of the cup molded product may be lost.

《Fusion》
The test sheet was divided into two by hand along the score line, and this divided section was visually observed. Then, in the divided cross section of the test sheet, the number of all the expanded particles (a) and the number of expanded particles (b) in which the expanded particles themselves were broken without breaking at the thermal fusion interface with each other were counted. The thermal fusion rate is calculated based on the following formula, and the result is shown in Table 1.
Thermal fusion rate (%) = 100 × b / a

<Measurement of adhesion rate of zinc stearate>
The adhesion rate of zinc stearate to the expandable polystyrene resin particles was calculated by quantifying the amount of zinc adhering to the expandable polystyrene resin particles before and after sucking and transporting, and calculating the percentage. That is, when the amount of zinc before suction transportation was W3 and the amount of zinc after suction transportation was W4, the adhesion rate of zinc stearate was determined by the following formula.
Zinc stearate adhesion rate (wt%) = 100 × W4 / W3

Zinc was quantified by the following method. 1.5 g of expandable polystyrene resin particles coated with zinc stearate are weighed accurately and incinerated at 450 ° C. for 3 hours. Then, 2 ml of concentrated hydrochloric acid is added, and the volume is made up to 25 ml with distilled water without filtration. It was. Using this ICP emission spectroscopic analyzer SPS-4000 manufactured by Seiko Denshi Kogyo Co., Ltd., photometric height 10.0 mm, high frequency output 1.30 kW, carrier flow rate 1.0 liter / minute, plasma flow rate 16.0 liter / minute. The zinc was quantified at an auxiliary flow rate of 0.5 l / min.
If the adhesion rate of zinc stearate is 80% or less, the oil content of the contents may ooze out and the commercial value of the cup molded product may be lost.

<Measurement of fluidity>
The fluidity was measured by the following method. The coated expandable polystyrene resin particles were put into a cylindrical container having a diameter of 80 mm and a height of 70 mm, and the height and diameter of a mountain formed when the container was raised were measured, and the angle of repose was calculated.
When this fluidity is 20 degrees or more, the fluidity of the resin is poor, the effect of preventing the oil from oozing out due to the peeling of the drug coated in the pipe during particle transfer occurs, and it takes time to transfer the particles. The problem occurs.

<Measurement of gas content>
Samples of expandable styrene resin particles (stored at 20 ° C. for 24 hours after production) 10-20 mg were precisely weighed and sealed in a 20 ml glass vial, set in a Perkins Elmer headspace sampler TurboMatrix HS40, and 160 ° C. The mixture was heated for 30 minutes and then quantified using a gas chromatograph Claras500GC (detector: FID) manufactured by Perkins Elmer. The measurement conditions in the headspace sampler are a needle temperature of 160 ° C., a sample introduction time of 0.08 minutes, a transfer line temperature of 160 ° C., and the measurement conditions in the gas chromatograph are DB-1 (0.25 mmφ × 60 m, membrane manufactured by J & W) Pressure 1 μm, Column temperature: 50 ° C. for 10 minutes, 20 ° C./minute, raised to 270 ° C., 270 ° C. for 1 minute), carrier gas helium (introduction conditions: 18 psi for 10 minutes, 0.5 psi / minute for 24 psi) And the inlet temperature (200 ° C.). The measured value was converted into a value for 100 parts by mass of the resin.

[Evaluation]
1. In any of the examples, compared with the comparative example, the foamed polystyrene resin particles are sucked and transported, the amount of the pre-foamed particles bonded, the oil content, the thermal fusion rate of the foamed particles, the adhesion rate of zinc stearate, the resin Good results in terms of fluidity.
2. In contrast, Comparative Examples 10 and 11 in which only polyethylene glycol A having a molecular weight of 300 or 400 and only polyethylene glycol B were not coated had a low adhesion rate of zinc stearate and a large peeling, and a yellow pigment formed by curry powder. There is a significant leak of oil. On the other hand, in Comparative Example 9 in which only polyethylene glycol B having a molecular weight of 300 was coated but not polyethylene glycol A, the oil content corresponding to the yellow pigment due to curry powder was poor because of the poor adhesion of zinc stearate. Leakage is remarkable.
3. In Comparative Example 7 in which polyethylene glycol having a molecular weight of 400 was used in two portions, the zinc stearate adhesion rate was poor, peeling was large, and oil leakage was significant. Also, the amount of bonding at the time of preliminary foaming is low. Further, in Comparative Example 8 in which polyethylene glycol having a molecular weight of 800 was used in two portions, the adhesion rate of zinc stearate was poor, peeling was large, and oil leakage was significant.
4). Moreover, even if it is the polyethylene glycol A of molecular weight 300 and the polyethylene glycol B of molecular weight 300, the comparative example 5 whose content is 0.005 weight part has bad adhesion rate of zinc stearate, peeling is large, and oil leaks Is remarkable.
Moreover, even if it is the polyethylene glycol A of molecular weight 300 and the polyethylene glycol B of molecular weight 300, the comparative example 6 whose content is 0.1 weight part adds to the fluidity | liquidity of resin, and a filling defect generate | occur | produces in addition. .
In the case of Comparative Example 1 in which 5.12 parts by weight of 5.12 hydroxystearic acid triglyceride, the thermal fusion rate of the expanded particles is lowered, and oil leakage tends to occur. On the other hand, in the case of Comparative Example 2 in which 12 parts of triglyceride 12hydroxystearate is 0.05 parts by weight, the thermal fusion rate of the foamed particles is good and no oil leakage occurs, but a lot of blocking occurs during preliminary foaming. Product efficiency is reduced. From Examples 3 and 4, 12-hydroxystearic acid triglyceride is preferably 0.003 to 0.04 parts by weight. From Examples 5 and 6, zinc stearate is preferably 0.2 to 0.8 parts by weight. In the case of Comparative Example 3 in which the zinc stearate is 1 part by weight, peeling is large and poor fusion occurs, but in the case of Comparative Example 4 in which the zinc stearate is 0.1 part by weight, the fluidity of the resin is reduced, Poor filling occurs.
6). Further, Comparative Example 12 in which polypropylene glycol A and polypropylene glycol B were replaced with polyethylene glycol A and polyethylene glycol B was inferior in resin flowability and zinc stearate adhesion rate, and had problems in terms of oil exudation.

The expandable styrenic resin particles of the present invention have no blocking at the time of pre-foaming, excellent flowability of the expanded particles, little peeling of the coated drug, good fusion, no oil leakage, and polyethylene glycol By coating in two separate steps, the drug coated on the surface is difficult to peel off when the resin is transferred, and the spreading effect of the drug can be improved.
In particular, food containers obtained by pre-foaming and molding expandable styrene resin particles for food containers can substantially suppress the penetration of contents with strong penetrating power including fats and oils, It can be used for instant noodles, curry, stew, mayonnaise, margarine, donut, hamburger, fried chicken, coffee and the like.

1 Hopper 11 Release Pipe 3 Suction Pipe 4 Bag Filter 6 Drum 7 Distribution Pipe

Claims (8)

Expandable styrene resin particles obtained by impregnating a styrene resin particle with a foaming agent, and the expandable styrene resin particles are coated with the resin particle surface, and the composition includes the resin particles Polyethylene glycol A covering the surface, 0.003 to 0.04 parts by weight of fatty acid triglyceride with respect to 100 parts by weight of the resin particles, and 0.2 to 0.8 parts by weight with respect to 100 parts by weight of the resin particles Of fatty acid metal salt and polyethylene glycol B,
The polyethylene glycols A and B contain 0.02 to 0.08 parts by weight with respect to 100 parts by weight of the resin particles, and are coated in two portions.
The polyethylene glycol A is a polyethylene glycol having a molecular weight of less than 400,
The expandable styrene resin particles, wherein the polyethylene glycol B is polyethylene glycol having a molecular weight of less than 400.   The expandable styrene according to claim 1, wherein the polyethylene glycol A contains 0.01 to 0.04 parts by weight with respect to 100 parts by weight of the resin particles, and the polyethylene glycol B contains 0.01 to 0.04 parts by weight. Resin particles.   3. The expandable styrenic resin particle according to claim 1, wherein the fatty acid triglyceride is 12-hydroxystearic acid triglyceride.   The expandable styrenic resin particles according to any one of claims 1 to 3, wherein the fatty acid metal salt is zinc stearate.   The expandable styrenic resin particles according to claim 4, wherein the foamed styrene resin particles are aggregates in which a plurality of zinc stearates are collected, and the average maximum diameter of the aggregates is 0.5 to 30 µm.   As an essential component of a readily volatile foaming agent in the expandable styrene resin particles that have passed 24 hours at 20 ° C. after producing the expandable styrene resin particles, pentane is added to 100% by weight of the expandable styrene resin particles. 6. Foaming according to any one of claims 1 to 5, characterized in that it contains 6% by weight, 0.01 to 1% by weight of propane, and the pentane has a weight ratio of isopentane of 10% to less than 30% by weight. Styrenic resin particles. The expandable styrenic resin particles according to any one of claims 1 to 6,
Polyethylene glycol is coated twice, and after the first coating of polyethylene glycol, a fatty acid triglyceride and a fatty acid metal salt are added and coated, and then the second coating of polyethylene glycol is performed. A method for producing resin particles. A molded product obtained by pre-foaming and molding the expandable styrene-based resin particles according to claim 1.

Images