JPH093146A - Production of epoxidized graft copolymer powder excellent in powder characteristics - Google Patents

Abstract

PURPOSE: To obtain an epoxidized graft copolymer powder which does not agglomerate during storage by coagulating a graft copolymer latex obtd. by grafting specific vinyl monomers onto a specific composite rubber. CONSTITUTION: This copolymer powder is produced by coagulating a graft copolymer latex obtd. by grafting at least one vinyl monomer giving a homopolymer having a glass transition point of 50 deg.C or higher (e.g. methyl methacrylate) and an epoxidized vinyl monomer (e.g. glycidyl methacrylate) onto a composite rubber which is formed from a polyorganosiloxane latex (e.g. a latex obtd. by specifically treating a mixture of γ- methacryloyloxypropyldimethoxymethylsilane and octamethylcyclotetrasiloxane) having a number average particle size of 10-100μm and a polyalkyl (meth) acrylate rubber (e.g. a rubber obtd. from n-butyl acrylate and allyl methacrylate).

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing an epoxy group-containing graft copolymer powder having excellent powder characteristics.

[0002]

2. Description of the Related Art Epoxy group-containing graft copolymers are excellent impact resistance improvers for imparting high impact resistance to thermoplastic resins such as polyester resins and polyphenylene sulfide resins. Kaihei 5-9
No. 385, etc.

[0003]

The graft copolymer usually obtained by emulsion polymerization is coagulated with an acid or salt and recovered as a powder.

The above-mentioned epoxy group-containing graft copolymer is also obtained by emulsion polymerization, and a method of coagulating and recovering with an acid or salt is adopted.

However, the recovery yield of the epoxy group-containing graft copolymer is poor when it is recovered by coagulation with the acid or salt, and the powders obtained are easily solidified during storage. There is a problem that automation of weighing and labor saving of transportation method are difficult.

[0006]

In view of such a situation, the inventors of the present invention have earnestly studied a method for producing an epoxy group-containing graft copolymer having excellent powder characteristics, and as a result, have a specific particle diameter. It was found that an epoxy group-containing graft copolymer powder having excellent powder characteristics can be obtained by using polyorganosiloxane particles, and the present invention has been accomplished.

That is, the gist of the present invention is to provide a composite rubber (A) comprising a polyorganosiloxane component (a-1) and a polyalkyl (meth) acrylate rubber component (a-2),
Graft copolymer obtained by graft-polymerizing one or more vinyl monomers (b-1) giving a polymer having a glass transition temperature of 50 ° C. or more and an epoxy group-containing vinyl monomer (b-2) An epoxy group-containing graft copolymer having excellent powder characteristics, characterized in that a polyorganosiloxane latex having a number average particle diameter of 10 to 100 nm is used in a method of coagulating latex to produce a graft copolymer powder. There is a method for producing powder.

The polyorganosiloxane latex having a small particle size used in the present invention is, for example, an organosiloxane mixture containing a diorganosiloxane and, if desired, a polyorganosiloxane graft crosslinker, or a polyorganosiloxane crosslinker. After homogenizing it with a homomixer that mixes with and homogenizes it with shearing force due to high-speed rotation, or a homogenizer that atomizes with a jet output from a high-pressure generator, drop it into a hot dodecylbenzenesulfonic acid aqueous solution. It can be obtained by polymerizing and then neutralizing dodecylbenzenesulfonic acid with an alkaline substance.

Examples of the diorganosiloxane used in the present invention include cyclic organosiloxanes having 3 or more membered rings, and those having 3 to 6 membered rings are preferably used. Specific examples of preferable cyclic organosiloxanes include hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, trimethyltriphenylcyclotrisiloxane, tetramethyltetraphenylcyclotetrasiloxane and octaphenylcyclo. Tetrasiloxane etc. can be illustrated, and these are used individually or in mixture of 2 or more types. The amount of cyclic organosiloxane used is preferably 60% by weight or more, and more preferably 70% by weight or more in the polyorganosiloxane.

In the present invention, a crosslinking agent for polyorganosiloxane can be optionally included. As the cross-linking agent for polyorganosiloxane, a trifunctional or tetrafunctional silane-based cross-linking agent, that is, a silane compound having three or four alkoxy groups is used, and specific examples thereof include trimethoxymethylsilane and triethoxyphenyl. Examples thereof include silane, tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, and tetrabutoxysilane. 4 as a cross-linking agent for polyorganosiloxane
Functional ones are preferred, and tetraethoxysilane is particularly preferred among the tetrafunctional crosslinking agents. The amount of the crosslinking agent for polyorganosiloxane used is 0 in the polyorganosiloxane.
-30% by weight is preferable, and 0-10% by weight is more preferable. Use of the polyorganosiloxane crosslinking agent in an amount exceeding 30% by weight does not contribute to the formation of a further crosslinked structure.

The present invention may further contain a graft crossing agent for polyorganosiloxane. The graft crossing agent for polyorganosiloxane means that the alkoxysilane part thereof is involved in the polymerization and is incorporated into the polyorganosiloxane, but at this time, it does not react and the poly (organosiloxane) in the presence of the polyorganosiloxane for the subsequent preparation of the composite rubber is used. Meta)
Acrylate rubber is a silane compound having a functional group that reacts during polymerization, and specific examples thereof include the following formula (1-1)
The compound etc. which can form the unit represented by (1-4) are used.

CH ₂ ═CR ² —COO— (CH ₂ ) _p —SiR ¹ _n O _{(3-n) / 2} (1-1) CH ₂ ═CH—SiR ¹ _n O _{(3-n) / 2} ( ^{_{1-2) CH 2 = CR 2 -C}} 6 H 4 -SiR 1 n O (3-n) / 2 (1-3) HS- (CH 2) p -SiR 1 n O (3-n) / 2 (1-4) (In the above formula, R ¹ is a methyl group, an ethyl group, a propyl group or a phenyl group, R ² is a hydrogen atom or a methyl group, n is 0, 1 or 2, and p is 1 to 6. Among these, (meth) acryloyloxysilane capable of forming the unit of the formula (1-1) has a high grafting efficiency and thus can form an effective graft chain, thereby exhibiting impact resistance. Is advantageous in terms of. Methacryloyloxysilane is particularly preferable as a unit capable of forming the unit of the formula (1-1).

Examples of the unit capable of forming the unit of the formula (1-2) include vinyltrimethoxysilane, vinylmethyldimethoxysilane and the like, and 4-vinyl as the unit capable of forming the unit of the formula (1-3). Phenyldimethoxymethylsilane, 4-vinylphenyltrimethoxysilane and the like can be exemplified, and as a unit capable of forming the unit of the formula (1-4), γ-
Examples thereof include mercaptopropyldimethoxymethylsilane, γ-mercaptopropyltrimethoxysilane and γ-mercaptopropyldiethoxyethylsilane.

Specific examples of methacryloyloxysiloxane include β-methacryloyloxyethyldimethoxymethylsilane, γ-methacryloyloxypropylmethoxydimethylsilane, γ-methacryloyloxypropyldimethoxymethylsilane, γ-methacryloyloxypropyltrimethoxysilane and γ-. Examples thereof include methacryloyloxypropyldiethoxymethylsilane, γ-methacryloyloxypropylethoxydiethylsilane, δ-methacryloyloxybutyldiethoxymethylsilane, and among these, γ-methacryloyloxypropyldimethoxymethylsilane and γ-methacryloyloxypropyltrisilane. Methoxysilane can be mentioned as a more preferable one. The amount of the grafting agent for polyorganosiloxane used is 0 to 10 in the polyorganosiloxane.
% By weight, preferably 0-5% by weight.

The number average particle size obtained by emulsion polymerization of such an organosiloxane mixture is 10 to 100 nm.
In the presence of the polyorganosiloxane of (a-
After the monomer for polyalkyl (meth) acrylate rubber as the component 2) is polymerized to form a composite rubber (A) composed of a polyorganosiloxane component and a polyalkyl (meth) acrylate rubber component, (b- 1) a vinyl monomer mixture containing at least one vinyl monomer that gives a polymer having a glass transition temperature of 50 ° C. or higher and (b-2) an epoxy group-containing vinyl monomer. By graft-polymerizing the above, an epoxy group-containing graft copolymer having excellent powder properties can be obtained.

The amount of polyorganosiloxane used in the present invention is 10 based on the total amount of the epoxy group-containing graft copolymer.
0% by weight is 0.5 to 90% by weight. If the amount of the polyorganosiloxane used is less than 0.5% by weight, the seed polymerizability of the subsequent composite rubber polymerization and graft polymerization will decrease, and the yield of the desired epoxy group-containing graft copolymer will decrease. Further, if the amount exceeds 90% by weight, the powder characteristics of the obtained graft copolymer deteriorate.

The number average particle diameter of the polyorganosiloxane used in the present invention must be in the range of 10 to 100 nm. When a polyorganosiloxane having a number average particle diameter of less than 10 nm is used, the performance of the resulting epoxy group-containing graft copolymer as an impact resistance-improving agent is deteriorated, and a polyorganosiloxane having a number average particle diameter of more than 100 nm is used. If so, the powder characteristics of the obtained epoxy group-containing graft copolymer are deteriorated.

The monomer for polyalkyl (meth) acrylate rubber which is the component (a-2) of the present invention comprises a specific alkyl (meth) acrylate and, if desired, a crosslinking agent for polyalkyl (meth) acrylate rubber, and It is a monomer mixture containing a graft copolymer for polyalkyl (meth) acrylate rubber, if desired.

Specific alkyl (meth) acrylates include linear or branched acrylates having an alkyl group having 1 to 8 carbon atoms and alkyl methacrylates having an alkyl group having 6 to 12 carbon atoms. Specific examples include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, s
ec-Butyl acrylate, 2-methylbutyl acrylate, 3-methylbutyl acrylate, 3-pentyl acrylate, hexyl acrylate, n-heptyl acrylate, 2-heptyl acrylate, n-octyl acrylate, 2-octyl acrylate, 2-ethylhexyl acrylate , Hexylmethacrylate, octylmethacrylate, decylmethacrylate, n-laurylmethacrylate, 2-ethylhexylmethacrylate and the like can be exemplified, and among these, n-butylacrylate can be exemplified as a preferable one.

As the cross-linking agent for polyalkyl (meth) acrylate rubber, (meth) acrylate having two or more polymerizable unsaturated bonds is used. Specific examples are ethylene glycol dimethacrylate, propylene glycol dimethacrylate, and 1,3. Examples include butylene glycol dimethacrylate and 1,4-butylene glycol dimethacrylate.

The graft-linking agent for polyalkyl (meth) acrylate rubber is polymerized with other components during polymerization for producing a polyalkyl (meth) acrylate rubber and incorporated into the rubber. At that time, at least a part of the polymerization is performed. A monomer having two or more polymerizable unsaturated bonds different in reactivity from each other so that a reactive unsaturated group remains without reacting and the residual unsaturated group can be polymerized together with the graft branch component during the subsequent graft polymerization. Specific examples include allyl methacrylate, triallyl cyanurate, triallyl isocyanurate, and the like. Allyl methacrylate partly reacts with both unsaturated groups to form a crosslinked structure during polyalkyl (meth) acrylate rubber polymerization, and the rest has only one unsaturated group reacting with the other unsaturated bond. It remains after the polymerization of the polyalkyl (meth) acrylate rubber, and during the subsequent graft polymerization, the remaining unsaturated bond reacts to form a graft bond, and thus functions as both a crosslinking agent and a graft crossing agent.

These polyalkyl (meth) acrylate rubber cross-linking agents and graft crossing agents may each be a single component or a combination of two or more components.
The amount of the crosslinking agent and the amount of the grafting agent to be used is 0 to 10
The amount is 10% by weight, and when only the allyl methacrylate is used as both a crosslinking agent and a graft crossing agent, it may be used in an amount of 0 to 20% by weight.

The amount of the polyalkyl (meth) acrylate rubber monomer used in the present invention is 0.5 to 90, based on 100% by weight of the entire epoxy group-containing graft copolymer.
% By weight. If it is less than 0.5% by weight, the pigment coloring property of the resin composition used as the impact resistance improver will be deteriorated, and if it is more than 90% by weight, the powder properties will be deteriorated.

Polymerization of monomers for polyalkyl (meth) acrylate rubber is carried out using sodium hydroxide, potassium hydroxide,
The above-mentioned monomer for alkyl (meth) acrylate rubber was added to the latex of polyorganosiloxane neutralized by the addition of an aqueous solution of alkali such as sodium carbonate, and the polyorganosiloxane particles were impregnated with a normal radical. It may be carried out by causing a polymerization initiator to act. As the polymerization proceeds, a latex of a composite rubber from which the polyorganosiloxane component and the polyalkyl (meth) acrylate rubber component cannot be substantially separated is obtained.

In the composite rubber, the main skeleton of the polyorganosiloxane component has a repeating unit of dimethylsiloxane, and the main skeleton of the polyalkyl (meth) acrylate rubber component has a repeating unit derived from n-butyl acrylate. Some are preferred.

The ratio of the polyorganosiloxane component to the polyalkyl (meth) acrylate rubber component in the composite rubber is preferably 1 to 99% by weight for the former and 1 to 99% by weight for the latter, and 5 to 95 for the former. Wt%, the latter 5-5
More preferably, it is 95% by weight.

There are no particular restrictions on the monomer constituting the component (b-1) of the present invention, which constitutes the one or more vinyl-based monomers which give the polymer having a glass transition temperature of 50 ° C. or higher, but it can be obtained. A glass transition temperature of the polymer of 50 ° C. or higher is necessary for good powder properties. Such vinyl monomers include aromatic alkenyl compounds such as styrene, α-methylstyrene and vinyltoluene; methacrylic acid esters such as methyl methacrylate and 2-ethylhexyl methacrylate; acrylic acid such as methyl acrylate, ethyl acrylate and butyl acrylate. Esters: various vinyl compounds such as vinyl cyanide compounds such as acrylonitrile and methacrylonitrile, and these may be used alone or in combination of two or more kinds.

The amount of one or more vinyl-based monomer mixture that gives a polymer having a glass transition temperature of 50 ° C. or higher is 100% by weight based on the total weight of the epoxy group-containing graft copolymer.
5 to 60% by weight. If it is less than 5% by weight, the powder properties will deteriorate, and if it is 60% by weight or more, the performance as an impact resistance improver will decrease.

As the epoxy group-containing vinyl monomer, glycidyl (meth) acrylate, vinyl glycidyl ether, allyl glycidyl ether, hydroxyalkyl (meth) acrylate glycidyl ether, polyalkylene glycol (meth) acrylate glycidyl ether, and diglycidyl. Examples thereof include itaconate, and among these, one or more selected from the group consisting of glycidyl (meth) acrylate and diglycidyl itaconate is preferable.

The amount of the epoxy group-containing vinyl monomer constituting the component (b-2) of the present invention used is 1 to 30% by weight based on 100% by weight of the entire epoxy group-containing graft copolymer.

Since the epoxy group-containing graft copolymer obtained in the present invention has an epoxy group, it is melt-mixed with a thermoplastic resin such as polyester resin, polycarbonate resin, polyamide resin or polyphenylene sulfide resin. Preferably, when the mixture is melt-kneaded using an extrusion group or the like, the epoxy group reacts with the residual functional group in the thermoplastic resin to partially form a bond between the graft copolymer and the thermoplastic resin. It acts as a compatibilizing agent for the group-containing graft copolymer and the thermoplastic resin, and improves the compatibility of the two, and thus the composition of the present invention can exhibit high impact strength.

Since the epoxy group-containing graft copolymer obtained in the present invention uses a polyorganosiloxane having a number average particle size of 100 nm or less, the thickness of the epoxy group-containing graft copolymer of the outer layer is a low Tg polymer. Is thin, and since it has a polymer layer having a Tg of 50 ° C. or higher inside thereof, there is no problem that the powders solidify during storage.

The present invention will be described below with reference to examples.

[0034]

EXAMPLES In the description, "parts" indicates "parts by weight". In addition, the measurement of various physical properties in each Example and Comparative Example is based on the following methods.

Average particle size: Dynamic light scattering method (DLS, Otsuka Electronics Co., Ltd.) using a sample solution prepared by diluting latex with water
800, temperature 25 ° C, scattering angle 90 °).

Blocking resistance: 20 g of dry powder,
Put in a cylinder with a diameter of 5 cm, and from the top of the cylinder 0.2 kg / c
A load of m2 was applied and the mixture was left at 30 ° C for 2 hours, and the block generated therein was vibrated at 60 Hz. Among the powders that had been disintegrated by this vibration, the weight of the powder that passed through 16 mesh was 60% of the weight of the block, and the blocking time was measured. The time of 20 seconds or less was passed.

Reference Example 1 Production of Polyorganosiloxane Latex L-1: γ-
0.5 parts of methacryloyloxypropyl dimethoxymethylsilane and octamethylcyclotetrasiloxane 9
9.5 parts were mixed to obtain 100 parts of a siloxane mixture.
To this, 300 parts of distilled water in which 1 part of sodium dodecylbenzenesulfonate was dissolved was added, and the mixture was mixed with a homomixer to obtain 10 parts.
After stirring at 000 rpm for 2 minutes, add 3 to the homogenizer.
It was passed twice at a pressure of 00 kg / cm @ 2 to obtain a stable premixed organosiloxane latex.

On the other hand, a separable flask equipped with a condenser and a stirring blade was charged with 10 parts of dodecylbenzenesulfonic acid and 90 parts of distilled water to prepare a 10% by weight dodecylbenzenesulfonic acid aqueous solution.

With the aqueous solution heated to 85 ° C., the premixed organosiloxane latex was added dropwise over 2 hours, and after the completion of the addition, the temperature was maintained for 3 hours and then cooled.
The reaction was then kept at room temperature for 12 hours and neutralized with aqueous sodium hydroxide.

The latex L-1 thus obtained was dried at 170 ° C. for 30 minutes to determine the solid content.
It was 8.1%. The number average particle size of the latex was 32 nm.

Reference Example 2 Production of Polyorganosiloxane Latex L-2: γ-
0.5 parts of methacryloyloxypropyl dimethoxymethylsilane and octamethylcyclotetrasiloxane 9
9.5 parts were mixed to obtain 100 parts of a siloxane mixture.
200 parts of distilled water in which 1.0 part each of sodium dodecylbenzene sulfonate and dodecylbenzene sulfonic acid were dissolved was prepared, and 100 parts of the above siloxane mixture was added thereto.
In addition to the above parts, the mixture was pre-stirred with a homomixer at 10,000 rpm and then emulsified with a homogenizer at a pressure of 200 kg / cm @ 2 to obtain an organosiloxane latex. This latex was transferred to a separable flask equipped with a condenser and a stirring blade, and stirred and mixed at 80 ° C.
After heating at 5 ° C for 5 hours and then standing at 20 ° C for 48 hours,
The pH of this latex was adjusted to 7. with an aqueous sodium hydroxide solution.
Neutralization to 0 gave Silicone Latex L-2.

The solid content of L-2 was 30.0%, and the number average particle diameter was 140 nm.

(Example 1) 55.2 parts of the silicone latex L-1 obtained in Reference Example 1 was sampled and placed in a separable flask equipped with a stirrer, 144.8 parts of distilled water was added, and nitrogen was added. After the substitution, the temperature was raised to 50 ° C., and a mixed solution of 74.8 parts of n-butyl acrylate, 0.2 part of allyl methacrylate and 0.3 part of tert-butyl hydroperoxide was added. Then, a mixed solution of 0.001 part of ferrous sulfate, 0.003 part of ethylenediaminetetraacetic acid disodium salt, 0.2 part of Rongalit and 10 parts of distilled water was added to start radical polymerization, and then the internal temperature was adjusted to 2 at an internal temperature of 70 ° C. It was kept for a time to obtain a composite rubber latex.

A mixed solution of 10 parts of methyl methacrylate and 0.05 part of tert-butyl hydroperoxide was added dropwise to this composite rubber latex in 15 minutes, and the mixture was kept at an internal temperature of 60 ° C. for 1 hour, and then 5 parts of glycidyl methacrylate and t.
A mixed solution of 0.025 parts of ert-butyl hydroperoxide was added dropwise over 8 minutes, and the internal temperature was maintained at 60 ° C. for 2 hours to complete the graft polymerization on the composite rubber, and the epoxy group-containing graft copolymer (A- A latex of 1) was obtained. The number average particle size of the A-1 latex was 71 nm.

A-1 latex at 40 ° C. with a concentration of 5% by weight
Was added to the calcium chloride aqueous solution so that the weight ratio of the latex and the aqueous solution was 1: 2, then the temperature was raised to 90 ° C. to coagulate, and the solid content was separated after repeating washing with water, It was dried at ℃ for 24 hours to obtain a dry powder of A-1.

The blocking time of the dry powder of A-1 was 4 seconds, and the powder characteristics were good.

(Comparative Example 1) The silicone latex L-2 obtained in Reference Example 2 was replaced with 53.2 parts of L-1 by 33.3.
And the amount of distilled water to be added is 144.8 parts to 166.
A dry powder of the epoxy group-containing graft copolymer (B-1) was obtained in the same manner as in Example 1 except that the amount was changed to 7 parts. The number average particle size of the B-1 latex was 305 nm.

B-1 dry powder has a blocking time of 300
It was more than a second, and the powder characteristics were poor.

[0049]

According to the present invention, an epoxy group-containing graft copolymer having excellent powder characteristics can be obtained,
The epoxy group-containing graft copolymer is useful as an excellent impact resistance improver for imparting high impact resistance to thermoplastic resins such as polyester resins and polyphenylene sulfide resins.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koji Matsumura 20-1 Miyukicho, Otake City, Hiroshima Prefecture Mitsubishi Rayon Co., Ltd. Otake Office

Claims (1)

[Claims] 1. A polyorganosiloxane component (a-1)
And a polyalkyl (meth) acrylate rubber component (a-
2) and a composite rubber (A) having a glass transition temperature of 50
One or more vinyl-based monomers (b
-1) and the epoxy group-containing vinyl monomer (b-2) are graft-polymerized to obtain a graft copolymer latex, and a graft copolymer powder is produced. A method for producing an epoxy group-containing graft copolymer powder having excellent powder characteristics, which comprises using a polyorganosiloxane latex having a particle size of ˜100 nm.