JP2001114808A - Acid-containing polymer latex and rubber latex having an enlarged particle size thereby - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubbery polymer (latex) having a moderately enlarged particle size and exhibiting high impact resistance and design properties, and an acid group-containing polymer latex which makes it possible. A latex which is excellent in productivity or industrial properties and has little rubber latex of a small particle diameter which does not enlarge. SOLUTION: Polyorganosiloxane (A) 1-90
In the presence of parts by weight, 5 to 10 monomer units containing an acid group
0% by weight, (meth) acrylic acid alkyl ester unit 0
To 95% by weight, other copolymerizable monomer units 0 to 5
0% by weight of polymer or copolymer (B) 10 to 9
An acid group-containing polymer latex in which 9 parts by weight ((A) + (B) = 100 parts by weight) are complexed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an acid group-containing polymer latex suitable for increasing the size of synthetic rubber, and a rubber latex having a particle size enlarged thereby.

[0002]

2. Description of the Related Art Conventionally, thermoplastic resins, for example, styrene-acrylonitrile copolymer resin, α-methylstyrene-acrylonitrile copolymer resin, styrene-acrylonitrile-phenylmaleimide copolymer resin, etc., impart compatibility with these resins. Formulating a graft polymer obtained by graft polymerizing a monomer such as a rubber-like polymer,
It is widely used in the world as a material imparted with impact resistance typified by ABS resin, ASA resin and the like. There is an appropriate region for the dispersed particle size of the rubber-like polymer used in these rubber-reinforced resins depending on the application.If the particle size is too small, the impact resistance cannot be exhibited. Not only that, but also the design of the resin, such as gloss and coloring, is impaired. Therefore, generally, 150 to 40
A rubber-like polymer dispersed particle size of about 0 nm is often employed. The dispersion particle size of the rubbery polymer (latex) obtained by emulsion polymerization is closely related to the production time.
For example, if a diene rubber latex exceeding 300 nm is to be directly produced by emulsion polymerization, it takes several tens of hours or more, which is extremely disadvantageous in productivity and is clearly disadvantageous from an industrial viewpoint. In order to improve such low productivity, a relatively small rubbery polymer latex of less than 150 nm was prepared in advance, and this was in some way used to produce a rubbery polymer having an average particle diameter of 150 to 400 nm. This is a technique called “bloat enlargement”. As a method of such enlargement, Japanese Patent Publication No. 42-3112 and Japanese Patent Publication No. 2-9601 disclose a method of adding an acid compound to a synthetic rubber latex.

[0003]

However, these methods have a problem that the latex becomes thin to avoid the generation of coagulates and the productivity is reduced. Also, Japanese Patent Publication No. 56-45921,
No. 301, JP-A-3-212401, JP-A-8-59704, and the like, an acid-containing diene or acrylic acid-containing polymer latex is added during or after the production of small particle synthetic rubber latex. by doing,
A method for producing a rubber latex that enlarges the particle size is disclosed. However, any of these methods has a problem that a large amount of rubber latex having a small particle diameter that does not increase in size remains.

The present invention has been made in order to solve the above-mentioned problems, and a rubber-like polymer (latex) having a moderately enlarged particle size and exhibiting high impact resistance and design properties, and the present invention has been made. An object of the present invention is to prepare a latex of an acid group-containing polymer, which is excellent in productivity or industrial property and hardly leaves a rubber latex having a small particle diameter which does not enlarge.

[0005]

DISCLOSURE OF THE INVENTION The present inventors have developed an acid group-containing polymer obtained by polymerizing a monomer or a monomer mixture containing an acid group-containing monomer as an essential component in the presence of a polyorganosiloxane. The present inventors have found that the above-mentioned problems can be solved by using a coalesced latex and have reached the present invention. That is, the acid group-containing polymer latex of the present invention comprises, in the presence of 1 to 90 parts by weight of a polyorganosiloxane (A), 5 to 100% by weight of an acid group-containing monomer unit and an alkyl (meth) acrylate 10 to 99 parts by weight of a polymer or copolymer (B) composed of 0 to 95% by weight of units and 0 to 50% by weight of other copolymerizable monomer units ((A) + (B) = 100 parts by weight) ) Is compounded.
Here, the alkyl (meth) acrylate desirably has an alkyl group having 1 to 12 carbon atoms. In the rubber latex of the present invention having an enlarged particle size, the acid group-containing polymer latex is used in an amount of 0.01 to 10 parts by weight based on 100 parts by weight (as solids) of a synthetic rubber latex.
Parts by weight are added. Here, as the synthetic rubber latex, a diene rubber latex, an acrylic rubber latex, or a mixture thereof is desirable.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The polyorganosiloxane (A) used in the present invention is not particularly limited, but is preferably a polyorganosiloxane containing a vinyl polymerizable functional group. More preferably, it is composed of 0.3 to 3 mol% of a siloxane unit having a vinyl polymerizable functional group and 97 to 99.7 mol% of a dimethyl siloxane unit, and a silicon atom having three or more siloxane bonds is contained in the polydimethylsiloxane. 1 for all silicon atoms
It is a polyorganosiloxane consisting of at most mol%. As a method for producing the polyorganosiloxane, for example, a latex obtained by emulsifying a mixture of dimethylsiloxane and a siloxane-containing functional group-containing siloxane, or a mixture containing a siloxane-based cross-linking agent as needed with an emulsifier and water, is used. After homogenization using a homomixer that atomizes by shearing force due to rotation or a homogenizer that atomizes by jet power from a high-pressure generator, polymerize at high temperature using an acid catalyst, and then acidify with an alkaline substance. Neutralization method and the like can be mentioned. Examples of the method of adding the acid catalyst used for the polymerization include a method of mixing with a siloxane mixture, an emulsifier and water, and a method of dropping an emulsified product of the siloxane mixture into fine particles at a constant rate in a high-temperature acid aqueous solution. Considering the ease of controlling the particle size of the siloxane, a method of dropping an emulsion in which the siloxane mixture is finely divided into a high-temperature aqueous acid solution at a constant rate is preferred.

The dimethylsiloxane used for producing the polyorganosiloxane includes a dimethylsiloxane-based cyclic body having three or more member rings, and a three- to seven-membered ring is preferable. Specific examples include hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, and the like. These may be used alone or as a mixture of two or more. In addition, the vinyl-polymerizable functional group-containing siloxane contains a vinyl-polymerizable functional group and can be bonded via a dimethylsiloxane bond. Various alkoxysilane processed products are preferred. Specifically, β-methacryloyloxyethyldimethoxymethylsilane, γ-methacryloyloxypropyldimethoxymethylsilane, γ-methacryloyloxypropylmethoxydimethylsilane, γ-methacryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropylethoxydimethylsilane, methacryloyloxysiloxanes such as γ-methacryloyloxypropyldiethoxymethylsilane and δ-methacryloyloxybutyldiethoxymethylsilane, vinylsiloxanes such as tetramethyltetravinylcyclotetrasiloxane, p-vinylphenyldimethoxymethylsilane, and γ-mercaptopropyl Dimethoxymethylsilane,
and mercaptosiloxanes such as γ-mercaptopropyltrimethoxysilane. These vinyl polymerizable functional group-containing siloxanes can be used alone or as a mixture of two or more. As the siloxane-based crosslinking agent, a trifunctional or tetrafunctional silane-based crosslinking agent, for example, trimethoxymethylsilane, triethoxydiphenylsilane, tetramethoxysilane, tetraethoxysilane,
Tetrabutoxysilane or the like is used. The amount of the polyorganosiloxane (A) used is 1 to 90 in the acid group-containing polymer latex ((A) + (B) = 100 parts by weight).
Parts by weight, preferably 3 to 80 parts by weight. When the amount is less than 1 part by weight, the residual amount of the rubber latex which is not enlarged and which is the main subject of the present invention increases, and when it exceeds 90 parts by weight, the proportion of the monomer unit containing an acid group is inevitably increased. Due to the decrease, it does not show the ability to enlarge.

Examples of the monomer containing an acid group include acrylic acid, methacrylic acid, itaconic acid and crotonic acid, and acrylic acid or methacrylic acid is particularly preferred. These can be used alone or in combination of two or more. As the alkyl (meth) acrylate, an alkyl (meth) acrylate having an alkyl group having 1 to 12 carbon atoms is preferable. As such a (meth) acrylic acid alkyl ester, an ester of acrylic acid or methacrylic acid and an alcohol having a linear or side chain having 1 to 12 carbon atoms is used. For example, methyl acrylate, ethyl acrylate, propyl acrylate,
N-butyl acrylate, isobutyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, methacrylic acid -T-butyl, 2-ethylhexyl methacrylate, and the like can be used, and particularly preferably an alkyl group having 1 to 8 carbon atoms. These can be used alone or in combination of two or more. Other copolymerizable monomers include aromatic vinyl monomers such as styrene, α-methylstyrene and p-methylstyrene; vinyl cyanide monomers such as acrylonitrile and methacrylonitrile; and other methacrylic monomers. Allyl acid, polyethylene glycol dimethacrylate, triallyl cyanurate, triallyl isocyanurate, compounds having two or more polymerizable functional groups such as triallyl trimellitate, and the like, and these may be used alone or in combination of two or more. Can be used.

The amount of the polymerizable monomer to be used is as follows: 100% by weight of the polymer or copolymer (B) ((A) + (B) = 99 to 10 parts by weight), acid 5 to 100% by weight, more preferably 8 to 90% by weight, a monomer unit having a group, 0 to 95% by weight of a (meth) acrylic acid alkyl ester unit having an alkyl group having 1 to 12 carbon atoms, It is from 0 to 50% by weight of a polymerizable monomer unit. When the proportion of the monomer unit containing an acid group is less than 5% by weight, the ability to enlarge is almost lost. Here, "composite" refers to polyorganosiloxane,
It refers to a state in which a polymer containing a monomer containing an acid group as an essential component is entangled at a micro level or chemically bonded to each other. Therefore, it may or may not have a chemical bond.

The method for producing the acid group-containing polymer latex is as follows:
In particular, any method may be used, but since the enlargement is performed by mixing the latexes, a monomer or a monomer mixture containing a monomer containing an acid group in the polyorganosiloxane latex as an essential component is used. It is preferable to carry out emulsion polymerization. As the emulsifier used in the emulsion polymerization, a sulfonic acid-based or sulfate-based emulsifier is used, and in particular, sodium alkylbenzenesulfonate, sodium alkylsulfonate, sodium dialkylsulfosuccinate, and sodium alkylsulfate are preferable. These can be used alone or in combination of two or more. Further, in addition to the above-mentioned sulfonic acid or sulfate ester emulsifiers, carboxylic acid emulsifiers exemplified by auxiliary oleic acid, palmitic acid, stearic acid, alkali metal salts of rosin acid, alkali metal salts of alkenyl succinic acid, etc. Can also be used. These can be used alone or in combination of two or more. These emulsifiers are used in an amount of 0.05 to 5 parts by weight based on 100 parts by weight of the total of the polyorganosiloxane and the monomer (mixture). The amount of the emulsifier used is the amount including that used for emulsification of the polyorganosiloxane. As a method of using the emulsifier, the whole amount may be charged at the beginning of the polymerization, or a part of the emulsifier may be used at the beginning and the rest may be added intermittently or continuously during the polymerization. Since the particle size of the acid group-containing polymer latex and, consequently, the particle size of the rubber latex having an enlarged particle size are affected by the amount of the emulsifier and the method of using the emulsifier, it is necessary to select an appropriate amount and the method of use. As the polymerization initiator used for the polymerization, a thermal decomposition type initiator, a redox type initiator and the like can be used. Examples of the thermal decomposition type initiator include potassium persulfate, sodium persulfate, ammonium persulfate, and the like, and examples of the redox type initiator include organic peroxides represented by cumene hydroperoxide-Rongalit-iron salt and the like. Is exemplified. These can be used alone or in combination of two or more. Besides these, mercaptans such as t-dodecylmercaptan and n-octylmercaptan, terpinolene, chain transfer agents such as α-methylstyrene dimer, etc., for adjusting the molecular weight, and alkalis for adjusting the pH, The addition of an electrolyte as an acid or a viscosity reducing agent is no problem.

In the production of the acid group-containing polymer latex, there is no particular limitation on the method of supplying the polyorganosiloxane and the monomer (mixture). May be supplied in advance, and the rest may be continuously or intermittently supplied into the system, or the entire amount may be supplied continuously or intermittently. However, since these supply methods affect the particle size of the acid group-containing polymer latex and, consequently, the particle size of the rubber latex having an enlarged particle size, it is necessary to select an appropriate use method. Particularly preferably, the total amount of the polyorganosiloxane is previously charged,
It is preferable to carry out the polymerization by supplying the whole amount of the monomer (mixture) continuously or intermittently thereto.

As the small particle synthetic rubber latex which can be subjected to the enlargement treatment with the acid group-containing polymer latex of the present invention, any rubber latex having a weight average particle diameter of less than 150 nm, which is not suitable for producing a synthetic resin, can be used. Although it does not matter, for example, polybutadiene rubber latex, butadiene-styrene copolymer latex (SBR), acrylate rubber latex, butadiene-acrylate copolymer latex, acrylonitrile-butadiene copolymer latex (NBR), chloroprene rubber latex , Isoprene rubber latex, ethylene-propylene rubber latex (EPR), ethylene-propylene-diene rubber latex (EPDM) and the like. From the industrial point of view of producing excellent ABS resin and ASA resin material, diene rubber latex, acrylic rubber latex or a mixture thereof is good,
Specifically, polybutadiene rubber latex, butadiene-styrene copolymer latex (SBR), acrylate rubber latex, and butadiene-acrylate copolymer latex are preferred. As the particle size of the small particle synthetic rubber latex to be used, from the industrial point of view of the enlargement treatment, since the significance of previously producing a large particle rubber latex is small, the weight average particle size is 150 n.
m or less is preferable. More preferably, it is 120 nm or less. When it exceeds 150 nm, not only industrial value is lost, but also it becomes difficult to enlarge.

Although any method may be used to obtain the enlarged synthetic rubber latex, for example, the acid group-containing polymer latex is added to the small particle rubber latex at once or dropwise under stirring, or intermittently. , A method of mixing a synthetic rubber latex and an acid group-containing copolymer latex simultaneously or while changing the timing, the small particle rubber latex is dropped or intermittently added to the acid group-containing polymer latex under stirring. And a method of adding an acid group-containing copolymer to latex during polymerization production of small particle synthetic rubber latex. Among them, a method in which the acid group-containing polymer latex is added to the small-particle rubber latex with stirring at once, dropwise, or intermittently is more preferable. The acid group-containing polymer latex is based on 100 parts by weight of synthetic rubber latex (as solid content).
It is desirable to add 0.01 to 10 parts by weight as a solid content. If the amount is less than 0.01 part by weight, the desired enlargement of the rubber latex having a large particle diameter cannot be obtained because the enlargement does not proceed sufficiently. On the other hand, if it is more than 10 parts by weight, the pH of the enlarged latex tends to decrease, and the latex tends to be unstable. The gist of the present invention is to facilitate the process of enlarging the particle size of rubber latex, and to reduce small particles that remain without being enlarged in view of the quality of the resin material. The amount of the remaining small particles of 150 nm or less is 15
% Or less, more preferably 10% or less.
If it exceeds 15%, there are problems such as the impact resistance of the rubber-modified resin material being insufficient and the moldability being deteriorated. The acid group-containing polymer latex according to the present invention and the synthetic rubber latex having a particle size enlarged thereby,
High impact polystyrene (HIPS) resin, AB
S-based resin, ASA-based resin, AES (acrylonitrile-
Manufacture of styrene resins such as EPDM-styrene resin and ACS (acrylonitrile-chlorinated polyethylene-styrene) resin, rubber reinforced MS (methyl methacrylate-
It can be used for the production of styrene) resins and rubber-reinforced PMMA (methyl methacrylate copolymer) resins.

[0014]

The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention. [Evaluation method] ・ Measurement of weight average particle diameter, amount of residual small particles of 150 nm or less The latex was directly observed with a transmission electron microscope to obtain particles 2
The particle sizes of 00 to 300 particles were measured, and their average particle sizes were determined.

[Production of polyorganosiloxane (A-1)] In a 5 L glass reactor equipped with a thermometer and a stirrer, 400 parts by weight of deionized water (hereinafter simply referred to as water) 5.0 parts by weight of sodium dodecylbenzenesulfonate Dodecylbenzenesulfonic acid 1.0 part by weight Octamethylcyclotetrasiloxane 99.0 γ-methacryloyloxypropyldimethoxymethylsilane 1.0 part by weight The mixture was preliminarily stirred at 10,000 rpm with a homomixer, and then 30 MPa with a homogenizer. The emulsified liquid emulsified and dispersed under pressure was added, heated at 80 ° C. for 5 hours, left at 20 ° C., and after 48 hours, the pH of the latex was neutralized to 7 with an aqueous sodium hydroxide solution to complete the polymerization. Polyorganosiloxane latet having a weight average particle size of 65 nm and a solid content of 19.5% by weight Box (A-1)
I got [Production of polyorganosiloxane (A-2)] In a 5-L glass reactor equipped with a thermometer and a stirrer, 150 parts by weight of deionized water (hereinafter simply referred to as water) 1.5 parts by weight of sodium dodecylbenzenesulfonate 1.5 parts by weight of dodecylbenzenesulfone 0.6 parts by weight of acid 99.5 parts by weight of octamethylcyclotetrasiloxane 90.5 parts by weight of γ-methacryloyloxypropyldimethoxymethylsilane A mixture of 0.5 parts by weight was preliminarily stirred at 10,000 rpm with a homomixer, and then a pressure of 30 MPa was applied with a homogenizer. The emulsion emulsified and dispersed in was added, heated at 80 ° C. for 5 hours, then left at 20 ° C., and after 48 hours, the pH of the latex was neutralized to 7 with an aqueous sodium hydroxide solution to complete polymerization, and the weight was reduced. Polyorganosiloxane latex having an average particle size of 150 nm and a solid content of 37.5% by weight (A-
2) was obtained.

[Production of Small Particle Synthetic Rubber Latex (X-1)] The following components were charged into a 10 L stainless steel autoclave equipped with a thermometer and a stirrer. Water 140 parts by weight Sodium oleate 1.0 parts by weight Potassium rosinate 1.5 parts by weight Rongalit C 0.2 parts by weight 0.2 parts by weight anhydrous sodium sulfate 0.2 parts by weight styrene monomer 2.6 parts by weight t-dodecyl mercaptan 0.2 parts by weight Part After replacing with nitrogen, 23.4 parts by weight of 1,3-butadiene was charged, and the internal temperature was raised to 55 ° C., and then an aqueous solution comprising the following components was injected to initiate polymerization. Ferrous sulfate heptahydrate 0.003 parts by weight Anhydrous sodium pyrophosphate 0.2 part by weight Water 10 parts by weight After 30 minutes from the initiation of polymerization, 7.4-butane-1,3-butadiene was added.
Parts by weight and a mixture consisting of 66.6 parts by weight of a styrene monomer were dropwise added thereto over 3 hours, and 1 hour after the start of the polymerization, 0.3 part by weight of n-dodecylmercaptan was pressed in, and from the start of the polymerization, The polymerization was continued at an internal temperature of 55 ° C. for up to 10 hours. After removing the remaining butadiene by steam distillation, the mixture was cooled, and a small particle synthetic rubber latex having a solid content of 40.1% by weight and a weight average particle diameter of 75 nm (X-
1) was obtained.

[Production of Small Particle Synthetic Rubber Latex (X-2)] In a 5 L glass reactor equipped with a thermometer and a stirrer,
The following components were charged, and the internal temperature was adjusted to 60 under stirring in a nitrogen atmosphere.
The temperature was raised to ° C. Water 200 parts by weight Sodium oleate 1.0 parts by weight Dipotassium alkenyl succinate 1.5 parts by weight Rongalit 0.2 parts by weight Dextrose 0.1 part by weight 0.1 parts by weight anhydrous sodium sulfate Ferrous sulfate / heptahydrate 0.005 parts by weight Disodium ethylenediaminetetraacetate 0.005 parts by weight 0.1 parts by weight of anhydrous sodium pyrophosphate To this, a mixture composed of the following components was supplied over 180 minutes. 99.4 parts by weight of n-butyl acrylate 0.4 parts by weight of allyl methacrylate 0.2 parts by weight of 1,3-butylene methacrylate 0.2 parts by weight of cumene hydroperoxide 0.2 hours by weight , Solid content 3
A small particle synthetic rubber latex (X-2) having 3.0% by weight and a weight average particle diameter of 70 nm was obtained.

[Production of Small Particle Synthetic Rubber Latex (X-3)] In a 5 L glass reactor equipped with a thermometer and a stirrer,
The following components were charged, and the internal temperature was adjusted to 60 under stirring in a nitrogen atmosphere.
The temperature was raised to ° C. Water 100 parts by weight Sodium oleate 0.5 parts by weight Dipotassium alkenyl succinate 0.8 parts by weight Rongalit 0.2 parts by weight Dextrose 0.1 parts by weight Anhydrous sodium sulfate 0.1 parts by weight Ferrous sulfate / heptahydrate 0.005 parts by weight Disodium ethylenediaminetetraacetate 0.005 parts by weight Anhydrous sodium pyrophosphate 0.1 part by weight Separately, 99.4 parts by weight of 2-ethylhexyl acrylate 0.4 parts by weight of allyl methacrylate 1.3 -Butylenedimethacrylate 0.2 part by weight Cumene hydroperoxide 0.2 part by weight Dipotassium alkenylsuccinate 0.7 part by weight 0.5 part by weight of sodium oleate 100 parts by weight of water A mixture composed of 100 parts by weight of a homomixer at 10,000 rpm. After the preliminary stirring, the monomer emulsified and dispersed at a pressure of 30 MPa by a homogenizer A containing emulsion was prepared. This emulsion was fed into the reactor over 180 minutes, and then held for an additional 60 minutes and then cooled to obtain a small particle synthetic rubber latex (X-3) having a solid content of 33.2% by weight and a weight average particle size of 85 nm. I got

[Production of Small Particle Synthetic Rubber Latex (X-4)] In a 5 L glass reactor equipped with a thermometer and a stirrer,
The following components were charged. Water 190 parts by weight Sodium oleate 0.5 parts by weight Sodium lauroyl sarcosinate 1.2 parts by weight Rongalit 0.2 parts by weight Dextrose 0.1 parts by weight N-butyl acrylate 11.0 parts by weight After nitrogen replacement, 1 part by weight 9.0 parts by weight of 1,3-butadiene were charged, and the internal temperature was raised to 45 ° C. Then, a mixture consisting of 0.003 parts by weight of ferrous sulfate and heptahydrate, 0.001 part by weight of disodium ethylenediaminetetraacetate, 0.1 part by weight of anhydrous sodium pyrophosphate, and 10 parts by weight of water was added to initiate polymerization. 50 internal temperature
The temperature was raised to ° C. Thirty minutes later, a mixture of 44 parts by weight of n-butyl acrylate and 36 parts by weight of 1,3-butadiene was added dropwise over 2 hours, and the internal temperature was kept at 50 ° C. for 8 hours from the start of polymerization. The polymerization was continued as it was. A small particle synthetic rubber latex (X-4) having a solid content of 32.2% by weight and a weight average particle diameter of 72 nm was obtained.

[Example 1] Production of acid group-containing polymer latex (C-1) In a 5 L glass reactor equipped with a thermometer and a stirrer, 50 parts by weight of a polyorganosiloxane latex (A-1, as a solid content) water (Including water in polyorganosiloxane latex) 320 parts by weight Rongalit 0.3 parts by weight Ferrous sulfate / heptahydrate 0.005 parts by weight Ethylenediaminetetraacetic acid / disodium 0.010 parts by weight Potassium oleate 2.0 The mixture was heated to 60 ° C. while stirring under a nitrogen atmosphere. To this, a mixture consisting of 38.0 parts by weight of n-butyl acrylate, 12.0 parts by weight of methacrylic acid and 0.2 part by weight of cumene hydroperoxide was supplied over 120 minutes (the internal temperature was controlled to be constant at 60 ° C.), After the completion, the temperature was further maintained for 120 minutes and then cooled. Solid content 24.8% by weight, weight average particle size 70n
m, acid group-containing polymer latex having a pH of 5.5 (C-
1) was obtained.

Example 2 Acid-Containing Polymer Latex (C-2) In a 5 L glass reactor equipped with a thermometer and a stirrer, 20 parts by weight of a polyorganosiloxane latex (A-1, solid content) (Including water in the organosiloxane latex) 200 parts by weight Rongalit 0.3 parts by weight Ferrous sulfate heptahydrate 0.005 parts by weight Ethylenediaminetetraacetic acid disodium 0.010 parts by weight Potassium oleate 2.0 parts by weight And the temperature was raised to 60 ° C. while stirring under a nitrogen atmosphere. To this, a mixture consisting of 65.0 parts by weight of n-butyl acrylate, 15.0 parts by weight of methacrylic acid, and 0.3 part by weight of cumene hydroperoxide was supplied over 120 minutes (the internal temperature was controlled to be constant at 60 ° C.). After the completion, the temperature was further maintained for 120 minutes and then cooled. Solids content 33.4% by weight, weight average particle size 65n
m, acid group-containing polymer latex having a pH of 5.3 (C-
2) was obtained.

Example 3 Production of Acid-Containing Polymer Latex (C-3) In a 5 L glass reactor equipped with a thermometer and a stirrer, 75 parts by weight of a polyorganosiloxane latex (A-1, solid content) water (Including water in polyorganosiloxane latex) 400 parts by weight Rongalit 0.15 parts by weight Ferrous sulfate / heptahydrate 0.005 parts by weight Ethylenediaminetetraacetic acid / disodium 0.010 parts by weight Potassium oleate 2.0 The mixture was heated to 60 ° C. while stirring under a nitrogen atmosphere. To this, a mixture consisting of 16.0 parts by weight of n-butyl acrylate, 11.0 parts by weight of methacrylic acid, and 0.15 parts by weight of cumene hydroperoxide was supplied over 120 minutes (controlling the internal temperature to be constant at 60 ° C.), After the completion, the temperature was further maintained for 120 minutes and then cooled. Solid content 20.1% by weight, weight average particle size 65n
m, acid group-containing polymer latex having a pH of 5.5 (C-
3) was obtained.

Example 4 Production of Acid-Containing Polymer Latex (C-4) The same procedure was followed as in Example 1 except that the polyorganosiloxane latex used was changed to (A-2). , Solid content 24.5% by weight, weight average particle size 12
An acid group-containing polymer latex (C-4) having a pH of 0 nm and a pH of 6.1 was obtained. [Example 5] Production of acid group-containing polymer latex (C-5) A polymer latex was prepared in the same manner as in Example 1 except that n-butyl acrylate used was changed to 2-ethylhexyl acrylate. An acid group-containing polymer latex (C-5) having a solid content of 24.3% by weight, a weight average particle diameter of 70 nm and a pH of 5.7 was obtained. [Example 6] Production of acid group-containing polymer latex (C-6) In the example described in Example 1, except that methacrylic acid used was changed to acrylic acid, solid content was 2
An acid group-containing polymer latex (C-6) having 3.8% by weight, a weight average particle diameter of 75 nm, and a pH of 5.2 was obtained.

Comparative Example 1 Production of Acid-Containing Polymer Latex (C-7) In a 5 L glass reactor equipped with a thermometer and a stirrer, 200 parts by weight of water 0.3 parts by weight of Rongalite Ferrous sulfate and hepatic water Salt 0.005 parts by weight Ethylenediaminetetraacetic acid disodium 0.010 parts by weight Sodium dodecylbenzenesulfonate 3.0 parts by weight Potassium oleate 2.0 parts by weight is added, and the mixture is heated to 60 ° C. while stirring under a nitrogen atmosphere. did. To this, a mixture consisting of 85.0 parts by weight of n-butyl acrylate, 15.0 parts by weight of methacrylic acid and 0.3 part by weight of cumene hydroperoxide was supplied over 120 minutes (controlling the internal temperature to be constant at 60 ° C.), After the completion, the temperature was further maintained for 120 minutes and then cooled. Solid content 33.0% by weight, weight average particle size 115n
m, acid group-containing polymer latex having a pH of 5.2 (C-
7) was obtained. Comparative Example 2 Production of Acid-Containing Polymer Latex (C-8) The following components were placed in a 5 L glass reactor equipped with a thermometer and a stirrer, and the temperature was raised to 60 ° C. while stirring under a nitrogen atmosphere. Polyorganosiloxane latex (A-1, as solid content) 97 parts by weight Water (including water in polyorganosiloxane latex) 600 parts by weight Rongalit 0.05 parts by weight Ferrous sulfate / heptahydrate 0.005 parts by weight 0.010 parts by weight of ethylenediaminetetraacetic acid disodium 2.0 parts by weight of potassium oleate 2.0 parts by weight of a mixture of 3.0 parts by weight of methacrylic acid and 0.05 parts by weight of cumene hydroperoxide were added to the mixture.
The mixture was supplied over a period of minutes (the internal temperature was controlled to be constant at 60 ° C.), and after the completion, the temperature was further maintained for 120 minutes and then cooled. An acid group-containing polymer latex (C-8) having a solid content of 14.1% by weight, a weight average particle diameter of 65 nm and a pH of 5.0 was obtained.

Example 7 In a glass container equipped with a stirrer,
At 25 ° C., 100 parts by weight of the small particle synthetic rubber latex (X-1, solid content) was charged, and 2.0 parts by weight of the acid group-containing polymer latex (C-1) was added all at once under stirring. . The stirring is continued for 30 minutes, and the weight average particle size is 32.
An enlarged synthetic rubber latex having a thickness of 0 nm was obtained. 4% by weight of residual small particles of less than 150 nm in this rubber latex
Met. [Examples 8 to 15 and Comparative Examples 3 and 4] In the same manner as in Example 7, the tex was changed with the acid group-containing copolymer latex or small particle synthetic rubber, and the results are shown in Table 1. .

[0026]

[Table 1]

As is apparent from the above, the use of the acid group-containing polymer latex of the present example makes it possible to easily obtain an enlarged synthetic rubber latex having few residual small particles. On the other hand, when an acid group-containing polymer latex that does not satisfy the requirements of the present invention is used, the number of remaining small particles increases and the enlargement itself does not progress.

[0028]

According to the present invention, a synthetic rubber latex having reduced residual small particles can be easily obtained by applying the acid group-containing polymer latex of the present invention. It is suitable for the production of rubber-modified styrene resins and the like.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08L 33:02) C08L 33:02) F-term (Reference) 4J002 AC031 AC061 AC071 AC081 AC091 BB151 BC073 BG013 BG041 BG043 BG053 BG103 CP032 HA07 4J011 KA04 KA07 KB08 PA99 PC02 PC06 4J100 AB02R AB03R AG69R AJ01P AJ02P AJ08P AL03Q AL04Q AL66R AL75R AM02R AQ21R BA08R BC43R CA04 CA05 EA07 FA02 FA20 GC19

Claims (4)

[Claims] 1. Polyorganosiloxane (A) 1 to 90
In the presence of parts by weight, 5 to 10 monomer units containing an acid group
0% by weight, (meth) acrylic acid alkyl ester unit 0
To 95% by weight, other copolymerizable monomer units 0 to 5
0% by weight of polymer or copolymer (B) 10 to 9
An acid group-containing polymer latex, wherein 9 parts by weight ((A) + (B) = 100 parts by weight) are complexed. 2. The acid group-containing polymer latex according to claim 1, wherein the alkyl (meth) acrylate has an alkyl group having 1 to 12 carbon atoms. 3. An acid group-containing polymer latex according to claim 1 is added in an amount of 0.01 to 10 parts by weight as a solid to 100 parts by weight (as a solid) of the synthetic rubber latex to increase the particle size. Rubber latex. 4. The rubber latex according to claim 3, wherein the synthetic rubber latex is a diene rubber latex, an acrylic rubber latex, or a mixture thereof.