JP3145864B2 - Method for producing methacrylic impact-resistant resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a methacrylic impact-resistant resin composition which gives an injection-molded article, an extruded sheet and a film which is excellent in the dispersibility of fine particles of a polymer having a multi-layer structure and in which generation of bumps is remarkably improved. About the method.

[0002]

2. Description of the Related Art Methacrylic resin is colorless and transparent, has a beautiful appearance and weather resistance, and is easy to mold. Therefore, louvers, tail lamps, lenses, tableware, and other electric parts, vehicle parts, optical applications, decoration, miscellaneous goods, and signboards. Although it is widely used, its impact strength is not always sufficient, and many improvements and modifications have been studied, and it has been commercialized as a methacrylic impact resistant resin. However, although these commercially available methacrylic impact-resistant resins satisfy the intended impact resistance to some extent, the impact modifier, which is added to and mixed with a general-purpose methacrylic resin, is not completely compatible with the methacrylic resin. Since the particles are dispersed in a shape, the presence of aggregates or coagulated particles of the particles is the cause of the lumps.Especially, a small amount of agglomerates are observed as lumps on the surface at the time of forming a sheet or in a thin film. At present, there is no satisfactory product.

[0003]

SUMMARY OF THE INVENTION The present invention relates to a methacrylic impact-resistant resin composition which is excellent in dispersibility of fine particles of a multi-layered polymer, and has significantly improved the generation of bumps in injection molded articles, extruded sheets and films. The purpose is to find a method of manufacturing a product.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies on a methacrylic impact-resistant resin in which the generation of bumps is remarkably improved. As a result, a multilayer structure polymer obtained by emulsion polymerization and a hard thermoplastic polymer are obtained. Is uniformly mixed in a latex state, then coagulated and taken out by any method, once obtained an impact resistance improver, and then melt-mixed with a hard methacrylic resin so that the dispersibility of the multilayer polymer fine particles is extremely good. It was found that the occurrence of bumps was remarkably improved, and the process for producing the methacrylic impact-resistant resin composition of the present invention was completed. That is, the present invention relates to (1) 50 to 99.9% by weight of at least one alkyl acrylate having 1 to 8 carbon atoms in an alkyl group, and 0 to 50% by weight of an unsaturated monomer copolymerizable therewith. At least one soft polymer layer obtained by polymerizing a monomer mixture comprising 0.1 to 5% by weight of a polyfunctional crosslinkable monomer and / or a polyfunctional graft monomer; Is from 50 to 100% by weight of at least one alkyl methacrylate having 1 to 4, 0 to 50% by weight of an unsaturated monomer copolymerizable therewith, a polyfunctional crosslinkable monomer and / or a polyfunctional graft monomer At least one alkyl group having an alkyl group having 1 to 4 carbon atoms, wherein the outermost layer is a combination of at least one hard polymer layer obtained by polymerizing a monomer mixture of 0 to 5% by weight. Methacrylate 50-100 % By weight, 0 to 50% by weight of an unsaturated monomer copolymerizable therewith
And a multilayer polymer 40 composed of a hard polymer layer obtained by polymerizing a monomer mixture in which the ratio of the outermost layer to the total amount of the soft polymer layer and the hard polymer layer is 10% by weight or more.
To 90 parts by weight, and (2) at least one alkyl methacrylate having 1 to 4 carbon atoms in the alkyl group.
0% by weight, 0 to 50 unsaturated monomers copolymerizable therewith
10 to 60 parts by weight of a hard thermoplastic polymer obtained by emulsion polymerization of a monomer mixture consisting of 100% by weight are uniformly mixed in a latex state, then coagulated and taken out to obtain an impact resistance improver. At least one alkyl methacrylate having from 1 to 4 carbon atoms in the alkyl group;
20 to 90 parts by weight of a hard methacrylic resin obtained by polymerizing a monomer mixture comprising 0 to 50% by weight of an unsaturated monomer copolymerizable therewith, and an impact modifier 10 to 80 parts by weight.
It is achieved by a method for producing a methacrylic impact-resistant resin composition excellent in dispersibility of multi-layered polymer fine particles, characterized by melt-mixing parts by weight.

The particle size of the polymer having a multilayer structure in the present invention is not particularly limited , but is preferably 0.08 to 0.35 μm.
When the particle diameter exceeds 0.40 μm, the occurrence of bumps increases rapidly, which is not preferable.

The particle size of the hard thermoplastic polymer in the present invention is not particularly limited , but is preferably 0.03 to 0.30.
μm, and more preferably smaller than the particle size of the multilayer structure polymer. The addition amount of the hard thermoplastic polymer is 10 to 60.
If the amount is less than 10 parts by weight, the dispersion of the multilayer polymer fine particles is unfavorably reduced. If the amount exceeds 60 parts by weight, there is a problem in terms of productivity. The molecular weight of the hard thermoplastic polymer is slightly different depending on the composition of the hard thermoplastic polymer, but is 40000 to 1300 in weight average molecular weight.
00 is preferred. If it is 40,000 or less, the impact strength is reduced, which is not preferable.

[0007] The method for producing a methacrylic impact-resistant resin composition of the present invention is characterized in that a multilayer structure polymer obtained by emulsion polymerization and a hard thermoplastic polymer are uniformly mixed in a latex state, and then coagulated to form a mixture. And an impact modifier, and then melt-mixed with a hard methacrylic resin.

[0008] Emulsion polymerization for obtaining the multilayer structure polymer and the rigid thermoplastic polymer in the present invention is a known method is used. The type and amount of the emulsifier used for emulsion polymerization,
It is selected depending on the stability of the polymerization system, the intended particle size, and the like. Known emulsifiers such as anionic surfactants, cationic surfactants, and nonionic surfactants can be used alone or in combination, and particularly, anionic surfactants can be used. Activators are preferred.
The polymerization initiator used for the emulsion polymerization is not particularly limited, and a persulfate-based or redox-based initiator is used. A chain transfer agent such as an alkyl mercaptan is used as needed.

In emulsion polymerization, a monomer, an emulsifier, a polymerization initiator, a chain transfer agent and the like are added by any method such as a batch addition method, a division addition method and a continuous addition method.

The method of uniformly mixing and precipitating and solidifying the respective polymer latexes obtained by emulsion polymerization is not particularly limited, and a salting out method, an acid precipitation method, a spraying method, a freezing method, and the like are possible.

The multilayer polymer according to the present invention comprises at least one soft polymer layer and at least one hard polymer layer, and the outermost layer is a hard polymer layer. The soft polymer layer in the multilayer polymer has an alkyl group having 1 carbon atom in terms of impact resistance and weather resistance.
At least one alkyl acrylate 50
To 99.9% by weight as a main monomer, 0 to 50% by weight of an unsaturated monomer copolymerizable therewith, a polyfunctional crosslinkable monomer and / or a polyfunctional graft monomer 0.1 to Consists of 5% by weight. As the alkyl acrylate used for the flexible polymer layer, methyl acrylate, ethyl acrylate, n
-Butyl acrylate, i-butyl acrylate, 2-
Ethylhexyl acrylate, cyclohexyl acrylate, benzyl acrylate and the like can be mentioned, and these are used alone or in combination. As unsaturated monomers copolymerizable with these, 1,3-butadiene, 2,3-butadiene, isoprene, styrene, α-methylstyrene, vinyltoluene, methyl methacrylate, ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, Benzyl methacrylate, acrylonitrile,
Methacrylonitrile and the like can be mentioned, and these are used alone or in combination. Examples of the polyfunctional crosslinkable monomer include ethylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, divinylbenzene, and the like. Examples include allyl methacrylate, allyl acrylate, allyl maleate, allyl fumarate, diallyl fumarate, triallyl cyanurate and the like, which are used alone or in combination.

The hard polymer layer of the multilayer polymer has an alkyl group having 1 to 4 carbon atoms in terms of transparency and weather resistance.
At least one alkyl methacrylate of 50 to 10
0% by weight is used, particularly preferably methyl methacrylate. The monomers copolymerizable therewith are 0 to 50% by weight of an unsaturated monomer, 0 to 5% by weight of a polyfunctional crosslinkable monomer and / or a polyfunctional graft monomer,
All monomers used in the soft polymer layer containing the alkyl acrylate can be used.

The outermost layer of the multilayer polymer is composed of a hard polymer layer in view of compatibility with a general-purpose methacrylic resin, and the ratio of the outermost layer to the total amount of the soft polymer layer and the hard polymer layer is 10%. % By weight or more. As the monomer constituting the outermost layer, at least one alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms is used in an amount of 50 to 100% by weight from the viewpoint of transparency and weather resistance, as in the case of the hard polymer. Particularly preferred is methyl methacrylate. The monomer copolymerizable therewith is 0 to 50% by weight of an unsaturated monomer, and is used in the hard polymer layer excluding a polyfunctional crosslinkable monomer and a polyfunctional graft monomer. All the monomers mentioned can be used. Further, a chain transfer agent such as n-octyl mercaptan or n-dodecyl mercaptan is preferably used from the viewpoint of compatibility with the hard methacrylic resin to be melt-kneaded.

[0014] Multi-layer structure polymer is by sequentially emulsion polymerizing a monomer mixture of each of these layers, obtained as the polymer latex.

[0015] Hardness Shitsunetsu thermoplastic polymers, transparency and the number of carbon atoms in the alkyl group from the weather resistance of the surface consists of at least one alkyl methacrylate 50-100% by weight is 1 to 4, particularly preferably methyl methacrylate is there.
The monomer copolymerizable therewith is an unsaturated monomer in an amount of 0 to 50% by weight, and excluding the polyfunctional crosslinkable monomer and the polyfunctional graft monomer. All monomers used in the polymer layer can be used. Further, a chain transfer agent such as n-octyl mercaptan and n-dodecyl mercaptan is preferably used from the viewpoint of compatibility with the multilayer structure polymer and general-purpose methacrylic resin. Further, the rigid thermoplastic polymer is obtained as a polymer latex by emulsion-polymerizing these monomer mixtures.

The method for producing the methacrylic impact-resistant resin composition of the present invention is obtained by uniformly mixing each of the above polymer latexes in a latex state, and then coagulating, separating and drying by any coagulating method. Certain impact modifiers 1 which may be coagulates or a mixture of different coagulates 1
0 to 80% by weight and specific hard methacrylic resin 20 to 9
The method is characterized in that 0% by weight is melt-mixed, and the methacrylic impact-resistant resin composition thus obtained is processed into an injection molding material such as a pellet, and into a sheet and a film by an extruder.

If necessary, ultraviolet absorbers, antioxidants, lubricants, dyes and pigments which are usually used for methacrylic resins can be added.

Injection molded articles, extruded sheet films, and processed articles made of the methacrylic impact-resistant resin composition obtained by the production method of the present invention have significantly reduced occurrence of bumps.

[0019]

EXAMPLES Next, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples.
“%” And “parts” in Examples are all “% by weight” and “parts by weight”, and refer to a monomer used, a polymerization initiator,
The following abbreviations are used for the chain transfer agent and the like.

Methyl methacrylate (MMA), methyl acrylate (MA), ethyl acrylate (EA),
n-butyl acrylate (BA), styrene (ST),
Allyl methacrylate (ALMA), 1,3-butylene glycol dimethacrylate (BGDMA), n-octyl mercaptan (n-OM). The horizontal line (-) is used to separate monomers and the like used to form the same layer,
The diagonal lines (/) mean that the layers are different.

The properties of the methacrylic impact resistant resin composition and the occurrence of bumps in the examples were as follows: a 3 mm extruded plate obtained by a 50φ sheet extruder equipped with three mirror-finished rolls, and injection molding after pelletization. Evaluation was performed using a 3 mm mirror flat plate obtained by a machine.

The evaluation of the occurrence of bumps is indicated by the following abbreviations. Very many spots… ×× There are spots… × No spots… 物 Evaluation of the physical properties of the resin composition and the like in the examples was measured according to the following method. (1) Heat deformation temperature; HDT ASTM-D6
48 (264 psi) (2) Izod impact strength (with notch) ASTM-D2
56 (3) Total light transmittance, haze ASTM-D1
003 (5 mm thickness) (4) Particle size Measured with an electron microscope. Example 1 (1) Production of multilayer polymer (A-1) latex 200 parts of ion-exchanged water was placed in a reaction vessel equipped with a reflux condenser.
After charging 2 parts of sodium stearate and raising the temperature to 80 ° C. while stirring under a nitrogen atmosphere, 19.5 parts of MMA, EA
0.5 part, a monomer mixture consisting of 0.12 parts of ALMA,
And 2 parts of a 1% KPS aqueous solution were charged and reacted for 60 minutes to complete the polymerization. Subsequently, when 5 parts of a 1% KPS aqueous solution was charged, 41.3 parts of BA, 8.7 parts of ST, and ALM
The monomer mixture consisting of A1 part was continuously dropped for 60 minutes, the whole amount was charged, and the mixture was held for 60 minutes to complete the polymerization. Subsequently, after charging 3 parts of a 1% KPS aqueous solution, MMA28.
A monomer mixture consisting of 5 parts, 1.5 parts of MA, and 0.06 part of n-OM was continuously added dropwise over 40 minutes.
The polymerization was completed by holding for 0 minute to complete the multilayer structure polymer (A-
1) A latex was obtained. After the polymerization of each layer was completed, the latex was sampled, and it was confirmed by an electron microscope observation that no new particles were generated and the sequential polymerization was completely performed. The particle size of the obtained latex was 0.25 μm. The composition of this latex corresponds to (A-1) in Table 1. (2) Production of rigid thermoplastic polymer (B-1) latex 200 parts of ion-exchanged water was placed in a reaction vessel equipped with a reflux condenser.
After charging 4 parts of sodium stearate and heating to 75 ° C. while stirring under a nitrogen atmosphere, 47 parts of MMA, MA3
Parts, a monomer mixture consisting of 0.15 parts of n-OM, and 5 parts of a 1% KPS aqueous solution were charged and reacted for 60 minutes to complete the polymerization. Subsequently, when 1% part and 5 parts of KPS aqueous solution were charged, 47 parts of MMA, 3 parts of MA, n-OM 0.1
The monomer mixture consisting of 5 parts was dropped continuously for 60 minutes, and the whole amount was charged. Then, the mixture was held for 60 minutes to complete the polymerization. The particle size of the obtained latex was 0.18 μm. The composition of this latex corresponds to (B-1) in Table 1.

Each of the polymer latexes thus obtained was converted to a polymer having a multilayer structure (A-1).
70 parts and 30 parts of the hard thermoplastic polymer (B-1) were uniformly mixed in a latex state, and then added to a 3% aqueous solution of magnesium sulfate to carry out salting out coagulation, followed by washing and drying to obtain a polymer powder. 100 parts of the obtained polymer powder and 100 parts of parapet EH beads (a grade for extrusion molding, manufactured by Kuraray Co., Ltd.), which is a hard methacrylic resin (C-1) , were mixed with a super mixer, and extruded with a sheet extruder. The occurrence of bumps and various physical properties were measured and evaluated. Table 2 shows the results. Example 2 (1) Production of multilayer polymer (A-2) latex 200 parts of ion-exchanged water was placed in a reaction vessel equipped with a reflux condenser.
After charging 3 parts of sodium dioctylsulfosuccinate and heating to 85 ° C. while stirring under a nitrogen atmosphere, MMA33 was added.
Parts, 2 parts of MA, 0.15 part of ALMA, and 3.5 parts of a 1% KPS aqueous solution were charged and reacted for 60 minutes to complete polymerization. Subsequently, when 4.5 parts of a 1% KPS aqueous solution was charged, 36.5 parts of BA and ST8.
A monomer mixture composed of 5 parts of ALMA and 1 part of ALMA was continuously dropped for 60 minutes, the whole amount was charged, and the mixture was held for 60 minutes to complete the polymerization. Then, after charging 2 parts of 1% KPS aqueous solution,
A monomer mixture consisting of 19 parts of MMA, 1 part of MA and 0.05 part of n-OM was continuously added dropwise over 40 minutes, followed by holding for 60 minutes to complete the polymerization and complete the multilayer structure polymer (A
-2) A latex was obtained. After the polymerization of each layer was completed, the latex was sampled, and it was confirmed by an electron microscope observation that no new particles were generated and the sequential polymerization was completely performed.
The particle size of the obtained latex was 0.16 μm.
The composition of this latex corresponds to (A-2) in Table 1. (2) Production of rigid thermoplastic polymer (B-2) latex 200 parts of ion-exchanged water was placed in a reaction vessel equipped with a reflux condenser.
After charging 4 parts of sodium dioctylsulfosuccinate and heating to 80 ° C. while stirring under a nitrogen atmosphere, MMA18 was added.
, 2 parts of EA, 0.05 parts of nOM, and 2 parts of a 1% KPS aqueous solution were charged and reacted for 40 minutes to complete the polymerization. Subsequently, when 8 parts of a 1% KPS aqueous solution was charged, M
A monomer mixture consisting of 72 parts of MA and 8 parts of EA was continuously dropped for 90 minutes, and the whole amount was charged. After that, the mixture was held for 60 minutes to complete the polymerization. The particle size of the obtained latex is 0.07 μm
m. The composition of this latex is shown in Table 1 (B-
This corresponds to 2).

Each of the polymer latexes thus obtained was converted into a polymer in a multilayer structure (A-2).
80 parts and 20 parts of the hard thermoplastic polymer (B-2) were uniformly mixed in a latex state, then freeze-coagulated at −40 ° C. for 3 hours, melted ice in hot water at 75 ° C., and then dehydrated.
After drying, a polymer powder was obtained. The obtained polymer powder 100
Part and parapet GN beads (injection molding grade, Kuraray Co., Ltd.), which is a hard methacrylic resin (C-2 ) 1
00 parts were mixed with a super mixer, and the occurrence of bumps and various physical properties were evaluated. Table 2 shows the results. Examples 3 to 6 By the same method as in Example 1, a multilayer structure polymer (A-3), a (A-4) latex, and a hard thermoplastic polymer (B- 3) A latex was obtained. Table 1 shows the number of layers, composition, and particle size of these polymers.
Shown in

Table 2 shows the mixing ratio of each polymer in the latex blend, the mixing ratio with the hard methacrylic resin at the time of pelletization and sheeting, and the evaluation results of the obtained injection molded flat plate and extruded plate. No bumps were observed in the injection-molded flat plate and extruded plate obtained in these examples, and various physical properties satisfying the present invention including the Izod impact strength were obtained. Table 1 shows the methacrylic resins used in the examples. Comparative Examples 1-4 The multilayer polymer latex and the hard thermoplastic polymer latex in the examples were used, but the mixing ratio of each polymer in the latex blend was outside the scope of the claims of the present invention. Nothing was satisfactory, including buttocks. Table 2 shows the results.

[0026]

[Table 1]

[0027]

[Table 2]

[0028]

As described above, the production method of the present invention provides an injection-molded article which is excellent in dispersibility of fine particles of a multilayer structure polymer imparting impact resistance and in which the occurrence of bumps is remarkably improved.
Extruded sheets and films can be supplied, and are particularly effective for products requiring impact resistance and good surface properties.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C08L 33/08-33/12 C08L 51/00

Claims (2)

(57) [Claims] (1) 50 to 99.9 of at least one alkyl acrylate having 1 to 8 carbon atoms in the alkyl group.
% By weight, a monomer mixture comprising 0 to 50% by weight of an unsaturated monomer copolymerizable therewith, a polyfunctional crosslinking monomer and / or 0.1 to 5% by weight of a polyfunctional graft monomer. At least one soft polymer layer obtained by polymerization; at least one alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms in an amount of 50 to 100% by weight; 50% by weight, a polyfunctional crosslinkable monomer and / or a combination of at least one hard polymer layer obtained by polymerizing a monomer mixture comprising 0 to 5% by weight of a polyfunctional graft monomer, The outermost layer is composed of 50 to 100% by weight of at least one alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms and 0 to 50% by weight of an unsaturated monomer copolymerizable therewith. To the total amount with the hard polymer layer 40 to 90 parts by weight of a multilayer polymer composed of a hard polymer layer obtained by polymerizing a monomer mixture having a ratio of the outermost layer of 10% by weight or more, and (2) an alkyl group having 1 to 4 carbon atoms. A hard thermoplastic polymer 10 obtained by emulsion-polymerizing a monomer mixture comprising 50 to 100% by weight of at least one type of alkyl methacrylate and 0 to 50% by weight of an unsaturated monomer copolymerizable therewith.
After uniformly mixing -60 parts by weight in the latex state, the mixture is coagulated and taken out to obtain an impact resistance improver. (3) Then, at least one alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms is 50 to 100. weight%,
20 to 90 parts by weight of a hard methacrylic resin obtained by polymerizing a monomer mixture of 0 to 50% by weight of an unsaturated monomer copolymerizable therewith and 10 to 80 parts by weight of an impact modifier are melt-mixed. A method for producing a methacrylic impact-resistant resin composition excellent in dispersibility of multilayer structure polymer fine particles, characterized by comprising: 2. The particle diameter of the multilayer polymer is 0.08 to
The method for producing a methacrylic impact-resistant resin composition according to claim 1, wherein the rigid thermoplastic polymer has a particle diameter of 0.03 to 0.30 µm.