JPS61159407A - Production of suspension polymer particle - Google Patents

Abstract

PURPOSE:To produce suspension polymer particles low in a content of unreacted monomers and excellent in transparency and heat resistance, by suspension- polymerizing a specified (meth)acrylate ester and other polymerizable unsaturated monomers in a mixture of an organic solvent and an aqueous medium. CONSTITUTION:A monomer mixture (A) comprising 5-100wt% (meth)acrylate ester having a 7C or higher alicyclic structure in the molecule [e.g., tricyclo[5,2,1,0<2.6>]dec-8-yl] (meth)acrylate and 95-0wt% other polymerizable unsaturated monomers (e.g., styrene) are suspension-polymerized at 0-200 deg.C in the presence of a suspending agent, a suspending aid and a polymerization initiator in a mixture of 5-50wt%, based on component A, organic solvent (B) of a b.p. <=150 deg.C (e.g, propane) and a solubility in water of 10wt% (at 25 deg.C) and an aqueous medium (C) in an amount to provide a weight ratio of the total of components A and B to water of 1/1-1/4.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is directed to suspension polymerization of acrylic esters or methacrylic esters having an alicyclic structure having 7 or more carbon atoms in one molecule, with a small amount of unreacted monomers. This invention relates to a method for producing polymer particles.

(Prior Art) A method of manufacturing polymer particles by suspension polymerizing two various monomers in an aqueous medium has been known (for example,
Special Publication No. 29-1298, Special Publication No. 54-34797
Publication No. 1988-38860 2% Publication No. 1988-38860
Publication No. 2302.

JP-A-56-152812, JP-A-58-8960
Publication No. 3).

This kind of suspension polymerization is basically carried out by dispersing monomers in an aqueous medium in the presence of a dispersant.9
Dispersion aids, plasticizers, salts, etc. are further added to the polymerization system to adjust the stability and particle size of one polymerization.

Dispersion of plasticizer in polymer 1 The purpose is to obtain particles with less entrainment of the dispersant.

On the other hand, resin is attracting attention as a material for various lenses, optical fibers, optical connectors, optical disks, optical circuits, etc., and is also attracting attention for its application to electronic parts.

(Problems to be Solved by the Invention) However, by the conventionally known suspension polymerization method as described above, a polymer having a sterically bulky alicyclic structure that has desirable properties as a raw material for optical resins. It has become clear that when esters of acrylic acid or methacrylic acid are polymerized, it is difficult to extremely reduce the amount of unreacted monomer remaining in the resulting polymer particles.

When the bipolymer particles are used as an optical material, this unreacted material adversely affects optical properties such as hygroscopicity, heat resistance, and birefringence. Deterioration of these properties can be fatal as an optical material.

This also applies to applications to electronic components.

However, since such acrylic esters or methacrylic esters have extremely high boiling points, it is difficult to remove them by simple operations such as steam distillation. For this reason, it has become necessary to reduce the residual amount of high-boiling monomers as much as possible in the double polymerization step.

Therefore, as described above, the present invention is three-dimensionally bulky,
Moreover, it is an object of the present invention to provide a method for producing a polymer with extremely little residual monomer by suspension polymerization of acrylic ester or methacrylic ester having a high boiling point.

(Means and effects of rounding to solve the problem) The present invention provides an alicyclic structure having 7 or more carbon atoms in 9 molecules. The present invention relates to a method for producing polymer particles, characterized in that polymerization is carried out in the presence of 5 to 50% by weight of an organic solvent based on the total amount.

The above acrylic acid or methacrylic acid esters include:
Methacrylic acid tricyclo(5,11,0”)deca-8-
yl, acrylic acid tricycloC5, Z 1゜o @ 8
) Dec-8-yl, erbornyl methacrylate, norbornyl acrylate, norbornylmethyl methacrylate, norbornylmethyl acrylate.

Cyclododecyl methacrylate, cyclododecyl acrylate, tricyclo[5,Zl,O'')deca- methacrylate
8-yloxyethyl, tricycloacrylate (511
, 0Edec-8-yloxyethyl, and the like.

In the present invention, other polymerizable unsaturated monomers include unsaturated fatty acid esters, aromatic vinyl compounds, vinyl cyanide compounds, N-substituted maleimides, and the like.

Examples of unsaturated fatty acid esters include acrylic acid alkyl esters such as methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and stearyl acrylate; acrylic acids such as cyclohexyl acrylate, phenyl acrylate, and benzyl acrylate; Aromatic esters, acrylic esters such as glycidyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, hexyl methacrylate, and 2-ethylhexyl methacrylate.

Examples include alkyl methacrylates such as stearyl methacrylate, aromatic esters of methacrylate such as cyclohexyl methacrylate, phenyl methacrylate, and benzyl methacrylate, and methacrylic esters such as glycidyl methacrylate.

Examples of aromatic vinyl compounds include styrene, α-substituted styrene such as α-methylstyrene, α-ethylstyrene, chlorostyrene, and vinyltoluene.

There are nuclear substituted styrenes such as t-butylstyrene.

Examples of vinyl cyanide compounds include acrylonitrile and methacrylonitrile. N-fl substituted maleimides include N-methylmaleimide, N-ethylmaleimide,
N-Inglobilmaleimide.

Aliphatic N-substituted maleimides such as N-butylmaleimide and N-lacrylmaleimide; alicyclic N-substituted maleimides such as N-cyclohexylmaleimide;

N-phenylmaleimide, N-methylphenylmale)
", N-chlorophenylmaleimide, N-methoxyphenylmaleimide, and other aromatic N-substituted maleimides.

In order to obtain a polymer with excellent transparency and heat resistance, and good moldability, it is preferable to mix the polymerizable monomers used as follows.

(1) Acrylic acid or methacrylic acid ester having an alicyclic structure with 7 or more carbon atoms in the molecule (hereinafter referred to as ester).

These are referred to as "component (1)" and are blended so that the amount of ioo to 5% by weight and other polymerizable unsaturated monomers is 0 to 95% by weight. If the amount of component I is too small, it will be difficult to sufficiently achieve the above effects.

Among other polymerizable unsaturated monomers, when the amount of N-substituted maleimide increases, the heat resistance improves.

Since moldability tends to deteriorate, it is more preferable to mix in the following manner.

(2) Component 1 100-5% by weight N-substituted maleimide 0-50% by weight and other polymerizable unsaturated monomers 0-95% by weight, so that the total amount is 100% by weight.

Furthermore, in order to make the material particularly suitable as a molding material,
It is preferable that the glass transition point is not too low. For this? ’.

(3) Component 1 100-5% by weight -N-substituted maleimide 0-50% by weight Unsaturated monomer whose homopolymer glass transition point is 50°C or lower (hereinafter referred to as "component ■") 0-50% by weight; Other polymerizable unsaturated monomers: 0 to 95% by weight, so that the total amount is 100% by weight.

In this case, component (2) includes ethyl acrylate, propyl acrylate, butyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, butyl methacrylate, and hexyl methacrylate.

Examples include 2-ethylhexyl methacrylate.

According to the method for producing a polymer according to the present IIAK, a prism,
It is possible to obtain resins for six types of optical elements such as convensators, optical fibers, optical connectors, optical disks, and light-emitting diodes, but for this purpose, it is necessary not only to have transparency, heat resistance, and moldability, but also to have low birefringence. It is also required to have excellent properties in terms of properties and low hygroscopicity. For this purpose, it is particularly preferable to mix them as follows.

(4) Component 1 100-20% by weight N-
Substituted maleimide O~30ft% component■
0 to 30% by weight and 0 to 80% by weight of other polymerizable unsaturated monomers, so that the total amount is 100% by weight.

Furthermore, if all the above characteristics are satisfied, then yo! To obtain a 7th product, mix as follows.

(5) Component 1 100-50wt-N-substituted maleimide 0-30wt% component n
o to 3o% by weight and other polymerizable unsaturated monomers from 0 to 50% by weight, so that the total amount is 100% by weight.

Furthermore, in the above (5), butyl acrylate, ethyl acrylate, or cyclohexyl acrylate is used as component (2), and methyl methacrylate and styrene are used as other polymerizable unsaturated monomers.

α-substituted styrene, nuclear-substituted styrene, acrylonitrile, etc. are preferred.

Organic bath agents that can be used in the present invention are not particularly limited, but include:
! ! ! In order to maintain dispersion stability during turbid polymerization, a solvent with low water solubility is preferred. In addition, in order to easily remove the solvent from the polymer particles after the completion of bipolymerization, K has a boiling point of 150°C.
The following bath additives are preferred.

The organic solvent that can be used in the method of the present invention preferably has a solubility in water of 10% by weight or less at 25°C2. For example, paraffinic hydrocarbons2 such as propane, butane, hexane, heptane, octane, etc. , 22-dimethylbutane, petroleum ether, petroleum benzyl, ligroin, gasoline.

Petroleum spirit, petroleum naphtha, pen/tene, cyclohexane methyl cyclohexane, etc., aromatic hydrocarbons 1, e.g. benzene, toluene, xylene, ethylhenzene, etc., alcohols with low water solubility, 1 e.g. n-butanol, isobutanol, amyl alcohol, etc. Tanol, methyl amyl alcohol, ethyl butanol etc. are used as ethers 1 such as ethyl ether, isopropyl ether, n-
Examples include butyl ether, furan, furfural, 2-methylfuran, and the like.

There is no particular restriction on the amount range of the organic solvent used.

The amount is preferably 5 to 50% by weight based on the total monomer amount. If the amount used is less than 5% by weight, the amount of residual monomer of component T (1) increases, which is not suitable for the purpose of the present invention. Also,
If it is added in an amount exceeding 50% by weight, dispersion stability decreases and it tends to become cake-like during polymerization. The upper limit of the amount of organic solvent used is preferably 30% by weight.

Moreover, (total amount of monomer and organic solvent)/(amount of water) is preferably 1/1 to 1/4 in a 2 weight ratio. If this ratio is too small, productivity will be poor, and if it is too large, it will be difficult to adjust the polymerization temperature and the two-dispersion stability will tend to decrease.

Examples of initiators used in the polymerization include benzoyl peroxide, lauroyl peroxide, di-t-butylperoxyhexahydroterephthalate, t-butylperoxy-2-ethylhexanoate, 1,1-di-t- Organic peroxides such as butylperoxy 3,3.5-trimethylcyclohexane, azobisinobutyronitrile, azobis-4-
Redox catalyst, etc. using a combination K of an azo compound such as methoxy-2,4-dimethylvaleronitrile, azobiscyclohexanone-1-carbonitrile, azodibenzoyl, peroxide or persulfate, and a reducing agent 2 Ordinary radical polymerization Any initiator that can be used can be used. The polymerization catalyst is preferably used in an amount of 0.01 to 10% by weight based on the total amount of monomers.

Furthermore, a polymerization regulator 9 such as a mercaptan compound, 1,000 glycol, carbon tetrabromide, α-methylstyrene gimer, etc. can be added as necessary to adjust the molecular weight.

The polymerization temperature is preferably selected appropriately between 0 and 200°C, particularly preferably between 50 and 120°C.

Suspension polymerization is carried out in an aqueous medium, with the addition of suspending agents and, if necessary, suspension aids. C. Holvinyl alcohol, methyl cellulose as suspending agents.

These include water-soluble polymers such as polyacrylamide, and sparingly soluble inorganic substances such as calcium phosphate and magnesium picophosphate.
The water-soluble polymer is used in an amount of 0.03 to 1% by weight based on the total amount of monomers, and the sparingly soluble inorganic substance is used in an amount of 0.03 to 1% by weight based on the total amount of monomers.
．． It is preferable to use 0.05 to 0.5% by weight.

As a suspension aid, sodium dodecylbenzene sulfonate I
There are anionic surfactants such as Jum, and l! ! When using a poorly soluble inorganic substance as a suspending agent, it is preferable to use a suspending aid in combination. The suspension aid is 0 based on the total amount of single substances.
．． It is preferable to use 0.001 to 0.02% by weight.

To remove the organic solvent from the polymer particles obtained in this way, there is a method of heating the particles in an atmosphere of steam or an inert gas such as nitrogen gas.

When using the polymer obtained by the present invention, from the viewpoint of preventing deterioration of the bipolymer and improving molding processability, antioxidants such as phenolic, thioether, and phosphite, lubricants, and antistatic agents, An ultraviolet absorber or the like may be added as necessary.

Tricyclo methacrylate (51
1,0”) dec-8-yl or tricyclo[
5,11,0'') dec-8-yl is obtained using generally known methods for the synthesis of methacrylic esters or acrylic esters.

For example, water is added to dicyclopentadiene to form zincloy/thenyl alcohol, followed by catalytic hydrogenation reaction to form tricyclo[5,λ1.0")deca-
It can be obtained by producing 8-ol, and conducting a condensation reaction between this alcohol and methacrylic acid, acrylic acid, methacrylic acid chloride, or acrylic acid chloride, or transesterification reaction with methyl methacrylate or methyl acrylate.

The polymer obtained by the present invention can be molded as a transparent resin and is used as a material for optical elements.

Resin 2 for electronic parts It can be applied to expandable thermoplastic resin particles, etc.

(Example) Next, the present invention will be explained in detail based on examples.

The present invention is not limited to this. In addition.

In the examples, "parts" means "parts by weight" unless otherwise specified.

Example 1 180 parts deionized water as the aqueous phase in the reaction vessel.

20 parts of calcium phosphate in a 10% aqueous suspension, 0.01 part of sodium dodecylbenzenesulfonate '7A.

0.2 part of sodium sulfate was added as an oil phase to tricyclo[5,21,0]dec-8-yl methacrylate (TCD-M
100 parts of A), 0.4 parts of lauroyl peroxide, 0.2 parts of n-octyl mercaptan, and 35 parts of toluene were charged, and while stirring, the atmosphere in the 2 reaction vessels was replaced with nitrogen gas, and the atmosphere in the 2 reaction vessels was replaced with nitrogen gas at 60°C. time, 2 hours at 90℃, 2 hours at 96℃
Polymer particles were obtained by polymerization for a period of time. The amount of residual TCD-MA monomer in this polymer particle was 0.07%, and the amount of toluene contained was 8.5%.

The polymer particles were transferred to a pressure-resistant container and heated with pressurized steam under an absolute pressure of 2.0 kg/cm" (temperature 110°C) for 1 hour.
When heating was continued for 0 hours, the TCD-MA monomer content of the two particles was 0.07%, and the toluene content was 0°12.
%. Further, the glass transition temperature was measured with a differential scanning calorimeter and found to be 176°C.

Example 2 Tricyclo(511,0"Edec-8-yl (TCD-AA) acrylate) instead of TCD-MA as a monomer
The operation was otherwise performed under the same conditions as in Example 1.

The TCD-AA monomer content of the obtained particles was o, o s
s, and the toluene content was 8.2%.

The TCD-AA monomer content in the particles after heating with pressurized steam was 0.05%, the toluene content was 0.13%, and the glass transition temperature was 106°C.

Example 3 The operation was carried out under the same conditions as in Example 1 except that 45 parts of n-heptane was used instead of 35 parts of toluene as the organic solvent. The TCD-MA monomer content of the obtained particles was 0.09%, and the n-hebutane content was 8.4%.

The TCD-MA monomer content in the particles after heating with pressurized steam for 10 hours was 0.08%, and the n-heptane content was 0.08%.
15%, and the glass transition temperature was 174°C.

Example 4 TCD-MA was used instead of 100 parts of TCD-MA as a monomer.
Using 85 parts of MA and 15 parts of styrene.

10 parts of xylene instead of 35 parts of toluene as an organic solvent
The operation was carried out under the same conditions as in Example 1 except for the following conditions. The TCD-MA monomer content of the obtained particles was 0.06%
, the styrene monomer content was 0.04 inch, and the xylene content was 4.2 inch.

The TCD-MA monomer content in the particles after heating with pressurized steam for 10 hours is 0.06%, and the styrene monomer content is 0.03.
%, the xylene content was 0.08%, and the glass transition temperature was 147°C.

Example 5 85 parts of TCD-MA and 15 parts of methyl methacrylate were used as monomers, except that the amount of isoamyl alcohol used as an organic solvent was 15 parts.

The same procedure as in Example 1 was carried out.

The TCD-MA monomer content of the obtained particles was 0.06
H. Methyl methacrylate monomer content is 0.05%.

The inoamyl alcohol content was 4.4%. When this polymer particle was heated with pressurized steam for 10 hours in the same manner as in Example 1, the TCD-MA monomer content was 0.06%.
The methyl methacrylate monomer content was 0.04% and the isoamyl alcohol content was 0.09%.

Note that the organic solvents used in Examples 1 to 5, toluene, n-
Heptane, xylene and isoamyl alcohol all have a solubility in water of 3% by weight or less.

Comparative Example 1 The operation was carried out under the same conditions as in Example 1 except that toluene was not used. The amount of residual TCD-MA monomer in the polymer particles was as large as 7.9%.

After heating with pressurized steam for 10 hours, the TCD-MA monomer content in the particles was 7.8%, which gradually decreased, and the glass transition temperature was 131 °C, compared to that of Example 1. It was significantly lower.

Comparative Example 2 The operation was carried out under the same conditions as in Example 1, except that TCD-AA was used instead of TCD-MA as a monomer and toluene was not used. The TCD-AA monomer content of the polymer particles was 6.7%, which was high.

After heating with pressurized steam for 10 hours, the TCD-AA monomer content in the particles was 6.5%, the content decreased slightly, and the glass transition temperature was 90°C.

(Effect of the invention) When suspension polymerizing esters of acrylic acid or methacrylic acid having a sterically extremely bulky alicyclic structure, it is difficult to reduce the amount of residual monomer using conventional suspension polymerization methods. However, when polymerization is carried out in the presence of an organic solvent according to the method of the present invention, the polymerization rate can be increased and the amount of residual monomer can be significantly reduced, and as a result, the glass transition temperature of the resulting polymer can be increased. Furthermore, the organic solvent can be easily removed by heating the resulting polymer particles in pressurized steam.

Claims (1)

[Claims] 1. 5 to 100% by weight of an ester of acrylic acid or methacrylic acid having an alicyclic structure having 7 or more carbon atoms in the molecule and 95 to 0% by weight of other polymerizable unsaturated monomers in an aqueous solution When carrying out suspension polymerization in a medium, polymerization is carried out in the presence of 5 to 50% by weight of an organic solvent based on the total amount of the ester of acrylic acid or methacrylic acid and other polymerizable unsaturated monomers. A method for producing turbid polymer particles. 2. The method for producing suspended polymer particles according to claim 1, wherein the organic solvent has low water solubility. 3. The method for producing suspended polymer particles according to claim 1 or 2, wherein the organic solvent has a boiling point of 150° C. or lower.