JPH08269386A - Acrylic paint resin manufacturing method - Google Patents

Abstract

(57) [Summary] [Purpose] To improve the physical properties and workability of acrylic paints, the object is to produce a resin for acrylic paints having a narrow molecular weight distribution and a low viscosity without decreasing the molecular weight. [Structure] Acrylic paint by a solution polymerization method using an alkyl hydroperoxide having at least 5 carbon atoms in a t-alkyl moiety such as t-amylperoxy-2-ethylhexanoate or a derivative thereof as a polymerization initiator. Of manufacturing resin for automobile.

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 resin for acrylic paint having improved physical properties and workability.

[0002]

2. Description of the Related Art Conventionally, acrylic paints have been used as a wide variety of paints for construction materials, automobiles, etc., and are required to have high durability, high extensibility, high appearance, abrasion resistance, and low odor. There is. Since there are many parts that depend on the acrylic resin as a raw material, in order to improve the physical properties of the acrylic resin, it has been attempted to make the resin high-solidified and have a high molecular weight. It is well known that a polymerization initiator such as an organic peroxide or an azo compound is used as a method for producing a resin for acrylic paint. For example, in JP-A-56-53115, an organic peroxide such as t-butyl hydroperoxide having a decomposition half-life at 100 ° C. of 10 minutes or more is used as a polymerization initiator, and a low molecular weight acrylic resin is used. A method of manufacturing is disclosed. In JP-A-3-64374, in order to obtain a matte coating composition, an organic peroxide such as t-butylperoxy-2-ethylhexanoate, an organic azo compound or the like is used,
A method for polymerizing acrylic paint resins is described.
However, when a derivative of t-butyl hydroperoxide is used as these polymerization initiators, when the molecular weight is increased to improve the resin performance, the branching degree is expanded and the viscosity is consequently increased. When an azo compound is used, branching can be suppressed to some extent, but the resin yield is significantly reduced due to its low reactivity, and (1) it is a solid and has limited solubility.
(2) The half-life temperature range is limited and low, so the decomposition rate is fast, the effect of the initiator is low, (3) recombination occurs and non-initiator species are generated, and (4) the degree of coloring of the resin is high. , (5)
It has drawbacks such as high toxicity of decomposition products.

[0003]

DISCLOSURE OF THE INVENTION In producing an acrylic paint resin, the present invention improves the physical properties and workability of the resin by producing a resin having a molecular weight equal to or higher than the conventional molecular weight and having a low viscosity. The purpose is to

[0004]

Means for Solving the Problems The inventors of the present invention have diligently studied to solve the problems of the above-mentioned conventional methods, and as a result, produced a resin having a molecular weight equal to or higher than the conventional molecular weight and having a low viscosity. The inventors have found a method for producing a resin for acrylic paints having improved physical properties and workability of the resin, and arrived at the present invention. That is, according to the present invention, an acrylic monomer is used as a polymerization initiator in the presence of about 0.5 to 10.0 parts by weight of an alkyl hydroperoxide having at least 5 carbon atoms in a t-alkyl portion or a derivative thereof. The present invention relates to a method for producing a resin for acrylic paint, which is characterized by performing solution polymerization. Generally, when the reaction kinetics are taken into consideration, the molecular weight of the polymer is increased and the molecular weight distribution is broadened when the amount of the polymerization initiator added is decreased.
-The use of alkyl hydroperoxide having at least 5 carbon atoms in the t-alkyl portion or its derivative as an alternative to a butyl hydroperoxide derivative or an azo initiator, this tendency is extremely small, and it is extremely suitable for acrylic paint resins. Work to your advantage.

The alkyl hydroperoxide having at least 5 carbon atoms in the t-alkyl moiety or its derivative used in the present invention has a weaker hydrogen abstraction force than conventional t-butyl peroxide and is a radical having excellent selectivity. To generate. The decrease in hydrogen abstraction force can narrow the molecular weight distribution (MWD) and lower the solution viscosity. Further, the alkyl hydroperoxide having at least 5 carbon atoms in the t-alkyl portion or a derivative thereof is (1) a liquid and excellent in solubility, (2) has a wide half-life temperature range, (3). It has advantages such as easy generation of free radicals.

Conventionally, it has been necessary to reduce the molecular weight in order to reduce the viscosity. However, when the addition ratio of the alkyl hydroperoxide or its derivative having at least 5 carbon atoms in the t-alkyl portion is reduced, It is possible to obtain a polymer product having a molecular weight equivalent to or higher than that when using -butyl peroxide, and its MWD is narrower and lower in viscosity than ever before.

Usually, radicals are considered to be kinetically
When the amount of the polymerization initiator added is reduced, the MWD is wide and the molecular weight is large, but within a certain range, the MWD is narrow and the change is small, which is an epoch-making result.

Since a resin having a narrow MWD and a low viscosity can be obtained even if the molecular weight is large, the physical properties and workability of the coating material using the resin are improved. Since the operation of the molecular weight becomes easy, it is possible to synthesize a resin according to the purpose. Since the addition rate of the polymerization initiator is lower than the conventional one, the cost efficiency of the process is improved.

In the polymerization of the present invention, an acrylic monomer, a polymerization initiator and a solvent are blended in a predetermined ratio, and the mixture is mixed for about 1 to 10 hours for about 9 minutes.
It is produced by solution polymerization heating to 0-200 ° C.
Generally, the ratio of solvent to monomer is 3: 1 to 0.1 :.
1. The initiator is about 0.1 to 100 parts by weight of the monomer.
The amount is 10.0 parts by weight, preferably 2.0 to 5.0 parts.
If it is 0.1 part by weight or less, the reaction efficiency is low and unreacted monomer remains, which is not preferable, and if it is 10 parts by weight or more, the reactivity is too high to obtain the desired resin performance. A preferred polymerization method comprises the controlled addition of monomers and initiator at a predetermined rate in a polymerization vessel containing a solvent at the desired temperature. The monomers and the initiators, alone or in combination, have an addition time of about 1 to 12 hours, preferably 3 to 10 hours.
Calculate the speed so that it will be time, and supply into the reactor. 1
It is difficult to obtain a uniform molecular weight within the time, and
It takes 12 hours or more, which is not economically disadvantageous. When the monomer and the initiator are separately metered and fed, the addition rates of both may be the same or different. Generally, the rates of addition of monomer and initiator are adjusted so that the rates of consumption / polymerization in the reaction solvent are approximately equal. Typically, the conversion of monomer to polymer that can be achieved at the end of the monomer / initiator addition is about 90.
~ 95% or more. The initiator is run at a half temperature at the polymerization temperature of about 1-60 minutes, preferably 5-20 minutes. If the half-minute temperature is 1 minute or more, it becomes difficult to control the reaction rate, and even if the polymerization is carried out at the half-minute temperature for 60 minutes or less, the reaction takes time, which is uneconomical. To prevent the unreacted monomer remaining in the polymerization system,
A normal polymerization initiator may be added as a supplementary catalyst.

The method of mixing and adding the monomer, the initiator, and the solvent is considered as follows, but any method may be selected as necessary. (1) A method of stirring while adding a mixture of a monomer, an initiator and a solvent into a polymerization system. (2) A method of adding a mixture of a monomer and an initiator to a solvent under stirring. (3) A method of stirring while adding a monomer, an initiator and a solvent.

The desired polymer product, for example, a peroxide derived from a t-alkyl hydroperoxide having 5 carbon atoms (that is, t-amyl hydroperoxide) is used as a polymerization initiator, and only the t-alkyl portion is used. In order to obtain a resin having the same molecular weight as the resin using different t-butyl hydroperoxide derivatives,
About 70-9 of t-butyl hydroperoxide derivative
0% by weight of t-amyl hydroperoxide derivative may be used.

The following are used as the monomer of the present invention. (1) As the ethylenic monomer having a hydroxyl group, hydroxyalkyl (meth) acrylates; 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, 3-hydroxypropyl acrylate, 3-hydroxybutyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, N-methylol acrylamide, allyl alcohol, etc., or compounds analogy therewith, (2) carboxyl group As the ethylenic monomer which has, acrylic acids; acrylic acid, methacrylic acid, crotonic acid, ethacrylic acid, propylacrylic acid,
Isopropyl acrylic acid, itaconic acid, musui maleic acid, fumaric acid, etc., or compounds similar to these,
(3) As other ethylenic monomers, (meth) acrylic acid alkyl ester, styrene, styrene derivative, addition reaction product with (meth) acrylic acid, methyl acrylate, ethyl acrylate, n-propyl acrylate, acrylic acid Isopropyl, n-butyl acrylate, isobutyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, methacrylic acid n
-Butyl, isobutyl methacrylate, n-methacrylic acid
Octyl, 2-ethylhexyl methacrylate, lauryl methacrylate, stearyl methacrylate, tridecyl methacrylate, and the like, or compounds analogy therewith. In addition, styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, pt
ert-butyl styrene, benzyl acrylate, benzyl methacrylate, itaconic acid ester, maleic acid ester, fumaric acid ester, acrylonitrile, methacrylonitrile, vinyl acetate, or the like, or compounds similar thereto, dimethylaminoethyl methacrylate, methacrylic acid Diethylaminoethyl, t-butylaminoethyl methacrylate, 3- (2-methacryloxyethyl)-
Adhesion promoter monomers such as 2,2-spirocyclohexyl oxolidene and the like can also be used. These (1)-(3)
These monomers may be used alone or in combination of two or more.

As the solvent used in the polymerization of the present invention,
Toluene, xylene, ethyl acetate, acetone, methyl ethyl ketone, methyl-n-amyl ketone, ethyl alcohol, oxo-hexyl acetate, oxo-heptyl acetate,
Propylene glycol methyl ether acetate and mineral spirits as well as other conventionally used aliphatic and aromatic hydrocarbons are used. Points to consider in choosing a suitable solvent are price, toxicity, volatility and chain transfer effects. Further, the type of the solvent has little effect on the performance of the initiator itself (molecular weight and MWD), but does affect the viscosity of the resin liquid.

The desired acrylic coating resin comprises one or more of the above monomers and one or more of an alkyl hydroperoxide having at least 5 carbon atoms in the t-alkyl moiety or a derivative thereof. It can be obtained by using it in a predetermined ratio and polymerizing it in a solvent.

The t-alkyl hydroperoxide having 5 or more carbon atoms or its derivative used in the practice of the present invention has a one-hour half-life temperature of 50 to 190 ° C, preferably 60 to 170 ° C. The initiator concentration used in the present invention is about 0.1 to 1 per 100 parts by weight of the monomer, either alone or in combination.
0.0 parts by weight, preferably about 2.0 to 5.0 parts by weight per 100 parts of monomer. If it is 0.1 part by weight or less, the reaction efficiency is low and unreacted monomer remains, which is not preferable, and if it is 10 parts by weight or more, the reactivity is too high to obtain the desired resin performance.

When the initiator concentration is low, a high molecular weight polymer can be easily produced, and when the initiator concentration is high, a low molecular weight polymer can be produced. Each of them has a narrower MWD than a polymer having the same molecular weight polymerized with a t-butyl hydroperoxide derivative and has a low viscosity. The initiator used in the present invention is 1,1-bis (t-amylperoxy) -3,3,5-trimethylcyclohexane, 1,1
-Bis (t-octylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane,
1,1-bis (t-amylperoxy) cyclohexane, 1,1-bis (t-octylperoxy) cyclohexane, 1,1-bis (t-hexylperoxy) cyclohexane, 2,2-bis (t- Amylperoxy) propane, 2,2-bis (t-octylperoxy) propane, 2,2-bis (t-hexylperoxy) propane, 2,2-bis (t-amylperoxy) butane,
2,2-bis (t-octylperoxy) butane, 2,
2-bis (t-hexylperoxy) butane, 3,3-
Bis (t-amylperoxy) pentane, 3,3-bis (t-hexylperoxy) pentane, 3,3-bis (t-octylperoxy) pentane, 2,2-bis (t-amylperoxy) Heptane, 2,2-bis (t
-Octylperoxy) heptane, 2,2-bis (t-
Hexylperoxy) heptane, n-butyl-4,4-
Bis (t-amylperoxy) valerate, n-butyl 4,4-bis (t-octylperoxy) valerate, n-butyl 4,4-bis (t-hexylperoxy) valerate, ethyl 3, 3-bis (t-amylperoxy) butyrate, ethyl 3,3-bis (t-octylperoxy) butyrate, ethyl 3,3-bis (t-hexylperoxy) butyrate, di-t-amylper Oxide, di-t-octyl peroxide,
Di-t-hexyl peroxide, 2,5-dimethyl-
2,5-di (t-amylperoxy) hexane, 2,5
-Dimethyl-2,5-di (t-octylperoxy) hexane, 2,5-dimethyl-2,5-di (t-hexylperoxy) hexane, 2,5-dimethyl-2,5-di (t -Amylperoxy) -3-hexyne, 2,5-dimethyl-2,5-di (t-octylperoxy) -3-
Hexine, 2,5-dimethyl-2,5-di (t-hexylperoxy) -3-hexyne, t-amylperoxy-2-ethylhexanoate, t-octylperoxy-2-ethylhexanoate , T-hexylperoxy-2-ethylhexanoate, t-amylperoxybenzoate, t-octylperoxybenzoate, t
-Hexyl peroxybenzoate, t-amyl peroxyisobutyrate, t-octyl peroxyisobutyrate, t-hexyl peroxyisobutyrate, t-
Amyl peroxy acetate, t-octyl peroxy acetate, t-hexyl peroxy acetate, t-
Amyl peroxypropionate, t-octyl peroxypropionate, t-hexyl peroxypropionate, di-t-amyl diperoxyazelate, di-
t-octyl diperoxyazelate, di-t-hexyl diperoxyazelate, di-t-amyl diperoxyphthalate, di-t-octyl diperoxyphthalate, di-t-hexyl diperoxyphthalate, OO-
t-amyl.O- (2-ethylhexyl) monoperoxycarbonate, OO-t-octyl.O- (2-ethylhexyl) monoperoxycarbonate, OO-t-
Hexyl.O- (2-ethylhexyl) monoperoxycarbonate, OO-t-amyl.O-isopropylmonoperoxycarbonate, OO-t-octyl.O-
Isopropyl monoperoxycarbonate, and OO
It is, but not limited to, -t-hexyl.O-isopropylmonoperoxycarbonate.

[0017]

EXAMPLES The contents of the present invention will be specifically described in the following examples, but it goes without saying that the technical scope of the present invention is not limited to these examples.

The abbreviations of the materials used in the examples mean the following, respectively. AIBN 2,2′-azobisisobutyronitrile Lup575 t-amylperoxy-2-ethylhexanoate TBPO t-butylperoxy-2-ethylhexanoate Lup531 1,1-bis (t-amylperoxy) ) Cyclohexane Lup331 1,1-bis (t-butylperoxy) cyclohexane TAPB t-amylperoxybenzoate TBPB t-butylperoxybenzoate BA butyl acrylate monomer BMA butyl methacrylate monomer HEA acrylate 2-hydroxyethyl monomer MAA methacryl Acid STY Styrene Mn Number average molecular weight MWD Molecular weight distribution

This example shows a conventional t in terms of polymer molecular weight (Mn), molecular weight distribution (MWD), viscosity, and color.
-Butyl peroxide, the performance of azo initiators have 5 carbon atoms
For the purpose of comparing it with that of peroxides derived from t-alkyl peroxides (i.e. t-amyl peroxide).

Upon polymerization, the amount of active oxygen (active nitrogen) used as an initiator was 0.42 phm as a reference, and the polymerization temperature was 15 minutes half-life temperature for comparison. The t-amyl peroxide was used in the same weight to 50% by weight as t-butyl peroxide in addition to 0.42 phm, and the same comparison was performed. The molecular weight and the molecular weight distribution are measured by gel permeation chromatography (GPC: Shimadzu Corp.). The viscosity is standardized to 80% solids and measured with a B-type viscometer. Color was determined with an APHA color number of 5 per step.

Examples 1 to 6 After replacing the inside of a 1000 ml four-necked flask equipped with a stirrer, an infusion pump, a reflux condenser, and a gas introduction pipe with nitrogen gas, 80 g of xylene was added. The temperature is raised to 103 ° C in an oil tank and the monomer (BA / BMA / HEA / HEA /
MAA / STY = 40/25/25 / 7.5 / 2.5)
A mixed solution of 300 g and Lup 575, 18.1 g was added at a uniform rate over 5 hours by an infusion pump. After addition 1
Polymerization was continued for a period of time. Furthermore, 300 g of the above monomer
And Lup 575, 17.0 g, 14.4 g, 13.6
Polymerization was similarly carried out for a solution prepared by mixing g, 10.2 g and 8.5 g. The number average molecular weight, molecular weight distribution, viscosity, and color number of each polymer were measured, and the results of comparison with Comparative Examples 1, 2, 3, and 4 are shown in Table 1.

Comparative Examples 1 and 2 In Example 1, the polymerization temperature was 106 ° C. and Lup575 was used.
Polymerization was carried out according to the method of Example 1 except that 17.0 g and 13.6 g of TBPO were used instead of.

Comparative Examples 3 and 4 Polymerization was carried out in the same manner as in Example 1 except that the polymerization temperature was 95 ° C. and 14.8 g and 12.6 g of AIBN were used instead of Lup575.

Table 1 ──────────────────────────────────── Usage amount Viscosity Color (parts by weight) Mn MWD (PS) (APHA) ──────────────────────────────────── Example 1 Lup575 6.03 4800 2.12 230 15 Example 2 Lup575 5.67 4900 2.22 350 15 Example 3 Lup575 4.81 5100 2.34 360 15 Example 4 Lup575 4.54 5300 2.43 370 15 Example 5 Lup575 3.40 5500 2.57 390 15 Example 6 Lup575 2.84 6300 2.66 400 15 Comparative Example 1 TBPO 5.67 5100 2.94 450 20 Comparative Example 2 TBPO 4.54 5500 3.32 480 20 Comparative Example 3 AIBN 4.93 5500 2.68 410 50 Comparative Example 4 AIBN 4.19 6300 2.95 480 50 ────────────────── ─────────────────── Example 1 having the same active oxygen (active nitrogen), Comparative Examples 1 and 3
The polymer of Example 1 has the narrowest MWD and viscosity. Mn of the polymer of Example 3 is Mn of the polymer of Comparative Example 1.
It has the same value as, but has a narrow MWD and a low viscosity. The Mn of the polymer of Example 5 is the same as that of the polymer of Comparative Example 3, but the MWD is narrow and the viscosity is low. AIBN is
Due to its poor solubility in solvents, it is difficult to add more than this,
Therefore, it is difficult to further reduce the molecular weight and viscosity. When the addition amount is reduced as in Comparative Example 4, the molecular weight is large, the distribution is wide, and the viscosity is increased.

Examples 7 to 11 In Example 1, the polymerization temperature was 124 ° C. and Lup575 was used.
Instead of Lup531, 11.3g, 10.2g,
Example 1 except using 9.2g, 8.2g, 6.2g
Polymerization was performed according to the method described in 1. The number average molecular weight, the molecular weight distribution, the viscosity and the color number of each polymer were measured to obtain Comparative Examples 5 and 6.
Table 2 shows the results of the comparison.

Comparative Examples 5 and 6 In Example 1, the polymerization temperature was 128 ° C. and Lup575 was used.
Polymerization was carried out according to the method of Example 1 except that 10.2 g and 8.2 g of Lup331 were used instead of.

Table 2 ──────────────────────────────────── Usage amount Viscosity Color (parts by weight) Mn MWD (PS) (APHA) ──────────────────────────────────── Example 7 Lup531 3.78 4600 2.91 340 15 Example 8 Lup531 3.41 4800 2.96 440 15 Example 9 Lup531 3.07 5100 3.00 470 15 Example 10 Lup531 2.73 5400 3.02 500 15 Example 11 Lup531 2.05 6000 3.10 530 15 Comparative Example 5 Lup331 3.41 5100 5.20 800 20 Comparative Example 6 Lup331 2.73 5900 5.35 880 20 ───────────────────────────────────── Example 7 having the same active oxygen The MWD and viscosity of Comparative Example 5 are narrower and lower in the polymer of Example 7. The Mn of the polymer of Example 9 is the same as that of the polymer of Comparative Example 5, but the MWD is narrow and the viscosity is low.

Examples 12 to 15 In Example 1, the polymerization temperature was 135 ° C. and Lup575 was used.
In place of 16.4 g, 15.3 g, 13.
Polymerization was carried out according to the method of Example 1 except that 0 g and 12.2 g were used. The number average molecular weight, molecular weight distribution, viscosity, and color number of each polymer were measured, and the results of comparison with Comparative Examples 7 and 8 are shown in Table 3.

Comparative Examples 7 and 8 In Example 1, the polymerization temperature was 138 ° C. and Lup575 was used.
Polymerization was carried out according to the method of Example 1 except that 15.3 g and 13.0 g of TBPB were used instead of.

Table 3 ──────────────────────────────────── Usage amount Viscosity Color (parts by weight) Mn MWD (PS) (APHA) ──────────────────────────────────── Example 12 TAPB 5.47 3300 2.85 180 40 Example 13 TAPB 5.09 3400 3.06 220 40 Example 14 TAPB 4.33 3500 3.12 250 40 Example 15 TAPB 4.07 3700 3.27 290 40 Comparative Example 7 TBPB 5.09 3500 3.97 330 55 Comparative Example 8 TBPB 4.33 3700 4.28 450 55 ─── ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── The polymer of Example 12 is narrower and lower. The Mn of the polymer of Example 14 is the same as that of the polymer of Comparative Example 7, but the MWD is narrow and the viscosity is low.

[0031]

As described above, a resin for acrylic paint having a narrow MWD and a low viscosity can be obtained even if the molecular weight is large, which is very useful for improving the physical properties and workability of the paint. . According to the production method of the present invention, the molecular weight can be easily manipulated so that the resin can be synthesized according to the purpose, and the addition rate of the polymerization initiator is lower than in the conventional case, so that the cost efficiency of the process is improved.

Claims (2)

[Claims] 1. A solution of an acrylic monomer in the presence of about 0.5 to 10.0 parts by weight of an alkyl hydroperoxide or a derivative thereof having at least 5 carbon atoms in a t-alkyl portion as a polymerization initiator. A method for producing a resin for acrylic paint, which comprises polymerizing. 2. The alkylhydroperoxide or its derivative is a peroxyketal, a dialkylperoxide, a peroxyester or a monoperoxycarbonate.
The manufacturing method described.