JP3666104B2 - Method for producing masterbatch comprising polymer particles in which fine polymer particles are dispersed - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to polymer particles in which fine polymer particles are dispersed. Specifically, the present invention relates to polymer particles for uniformly dispersing fine polymer particles in a molded body, that is, polymer particles serving as a master batch of so-called fine polymer particles.
[0002]
[Prior art]
In recent years, instead of inorganic powder, fine polymer particles are increasingly used as a resin light diffusing agent. In general, when inorganic powder is added to the base resin, there is a disadvantage that the light transmittance is greatly reduced even if sufficient light diffusibility is obtained, and the physical properties of the base resin such as impact strength are reduced. It also had drawbacks.
[0003]
Further, when a resin powder having a different refractive index, such as polystyrene or polymethyl methacrylate, is added to the base resin, the light diffusion effect is limited to some extent. In order to improve this, Japanese Patent Application Laid-Open No. 4-337304 discloses that a polymerizable vinyl monomer and fine polymer particles insoluble in the monomer are dispersed in an aqueous system and obtained by suspension polymerization. Polymer particles are disclosed.
[0004]
On the other hand, when the fine polymer particles are used as a light diffusing agent, the amount of the fine polymer particles in the molded body is about 0.01 to 0.05% by weight, which is very small. Therefore, the fine polymer particles are contained in the molded body resin. A great deal of effort is required to uniformly disperse the particles.
[0005]
[Problems to be solved by the invention]
An object of the present invention is to provide polymer particles in which fine polymer particles serving as a master batch of fine polymer particles are dispersed in order to facilitate uniform dispersion of the fine polymer particles in a molded body resin.
Conventional polymer particles in which fine polymer particles described in JP-A-4-337304 are dispersed have a molecular weight of about several hundred thousand to one million, are not easily melted, and have compatibility with a molded body resin. Not good.
[0006]
In view of such circumstances, the present inventor has made extensive studies on polymer particles in which fine polymer particles are easily dispersed, which facilitates uniform dispersion of fine polymer particles in a molded resin. After being dispersed in an aqueous system, suspension polymerization is carried out in the presence of a chain transfer agent to find that the resulting polymer particles can be easily melted and that the fine polymer particles can be easily dispersed uniformly in the molded resin. The invention has been completed.
[0007]
[Means for Solving the Problems]
That is, the present invention is as follows.
(1) A method for producing a masterbatch comprising polymer particles in which fine polymer particles having an MFR of 1 to 50 (g / 10 min) are dispersed ,
The insoluble fine polymer particles dispersed in an aqueous heavy polymerizable vinyl monomers and the monomer,
Method for producing a master batch, which comprises suspending polymerized in the presence of a chain transfer agent.
Hereinafter, the present invention will be described in detail.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The polymerizable vinyl monomer in the present invention is not particularly limited as long as it is capable of radical polymerization. For example, acrylic acid alkyl ester monomers such as methyl acrylate and butyl acrylate, and methacrylic acid such as methyl methacrylate and ethyl methacrylate. Representative examples include alkyl ester monomers, unsaturated carboxylic acids such as acrylic acid and methacrylic acid, and styrene monomers such as styrene, α-methylstyrene, and chlorostyrene.
A polyfunctional monomer having two or more radical polymerizable groups may be used, and examples thereof include divinylbenzene, ethylene glycol dimethacrylate, and trimethylolpropane triacrylate.
The polymerizable vinyl monomers are used alone or in combination of two or more.
[0009]
The polymer particles obtained by suspension polymerization of this polymerizable vinyl monomer have an MFR (measured under JIS K7210 condition 15) of 1 to 50 (g / 10 min). If it is less than 1 g / 10 minutes, the compatibility with the molded body resin is inferior, and if it is more than 50 g / 10 minutes, the mechanical strength and heat resistance are inferior.
[0010]
The fine polymer particles used in the present invention are insoluble in the polymerizable vinyl monomer and usually have an average particle diameter of 0.1 to 50 μm.
Examples of the fine polymer particles include silicone resin fine particles, polystyrene cross-linked fine particles, polymethyl methacrylate cross-linked fine particles, inorganic powder-containing polymethyl methacrylate cross-linked fine particles, and the like.
The fine polymer particles are usually used in an amount of about 0.01 to 1.0% by weight with respect to the polymerizable vinyl monomer, and the entire amount is dispersed in the polymer particles. This amount can be appropriately changed to an amount suitable as a master batch of fine polymer particles.
[0011]
The polymer particles in which the fine polymer particles are dispersed are produced by dispersing the fine polymer particles and the polymerizable vinyl monomer in an aqueous system, followed by suspension polymerization in the presence of a chain transfer agent. The fine polymer particles are preferably dispersed in the polymerizable vinyl monomer in advance before the polymerizable vinyl monomer is dispersed in the aqueous system.
[0012]
In the suspension polymerization, a granulation aid is used to prevent aggregation and coalescence of the polymer. This granulation aid is a variety of dispersants known in the suspension polymerization art, such as polyvinyl alcohol, hydroxy. Organic dispersants such as cellulose and inorganic salts such as calcium phosphate and aluminum hydroxide are used, and an anionic surfactant such as sodium dodecylbenzenesulfonate and sodium lauryl sulfate is also used as a suspension aid.
[0013]
As the polymerization initiator, since polymerization is usually performed at 50 to 120 ° C., any polymerization initiator that generates radicals at this temperature may be used. The type of the polymerization initiator is not particularly limited. For example, 2,2′-azobis (2.4-dimethylvaleronitrile), benzoyl peroxide, azobisisobutyronitrile, dimethyl 2,2′-azobisiso Peroxyesters such as azo compounds such as butyrate, tertiary butyl peroxypivalate, tertiary butyl peroxy 2-ethylhexanoate, cumylperoxy 2-ethylhexanoate, di-3,5,5- And diacyl peroxides such as trimethylhexanoyl peroxide and dilauroyl peroxide.
One or more of these are used.
The amount of the polymerization initiator used is preferably in the range of about 0.02 to 2 parts by weight with respect to 100 parts by weight of the polymerizable vinyl monomer.
[0014]
As the chain transfer agent, a known monofunctional or polyfunctional chain transfer agent can be used.
For example, alkyl mercaptans such as propyl mercaptan, butyl mercaptan, hexyl mercaptan, octyl mercaptan, 2-ethylhexyl mercaptan and dodecyl mercaptan: aromatic mercaptans such as phenyl mercaptan and thiocresol: mercaptans having 18 or less carbon atoms such as ethylenethioglycol: Examples include those obtained by esterifying a polyhydric alcohol hydroxyl group such as ethylene glycol, neopentyl glycol, trimethylolpropane, pentaerythritol, dipentaerythritol, tripentaerythritol, sorbitol with thioglycolic acid or 3-mercaptopropionic acid.
In addition, 1,4-dihydronaphthalene, 1,4,5,8-tetrahydronaphthalene, β-terpinene, terpinolene, 1,4-cyclohexadiene, hydrogen sulfide and the like can be used.
These can be used alone or in combination of two or more.
[0015]
The amount of chain transfer agent used varies depending on the type, but is usually 0.01 to 3 parts by weight, preferably 0.05 to 1 part by weight, based on 100 parts by weight of the polymerizable vinyl monomer . The amount used is preferable because it does not impair the mechanical strength of the polymer and maintains good thermal stability.
[0016]
In suspension polymerization, a polymerizable vinyl monomer, fine polymer particles, a polymerization initiator, and a chain transfer agent are added to water in which a dispersant, a suspension aid, and the like are dissolved, and usually under reaction conditions of 50 to 120 ° C. for a predetermined time. Done.
Various polymerization conditions can be selected according to the above MFR and the desired particle size of the polymer particles, and the concentration of the polymerizable vinyl monomer, the amount of the suspending agent, the stirring conditions, etc. are adjusted within the range described above. By doing so, the polymer particles of the present invention can be obtained.
The polymer particles obtained by the suspension polymerization are washed and dried to obtain polymer particles in which the fine polymer particles of the present invention are dispersed.
[0017]
【The invention's effect】
The polymer particles of the present invention are easy to melt and can easily disperse the fine polymer particles uniformly in the molded body resin.
[0018]
【Example】
Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited thereto.
The MFR was measured according to JIS K7210 Condition 15.
[0019]
Example 1
In a 5 L autoclave, 2460 g of water, 5.9 g of sodium monophosphate, and 51 g of 1.2% sodium polymethacrylate were placed. Next, 1920 g of methyl methacrylate, 113 g of methyl acrylate, 6.1 g of lauroyl peroxide, 8 g of lauryl mercaptan, and 15.5 g of silicone resin particles (Toshiba Silicone Co., Ltd .: Tospearl 145) as fine polymer particles were placed in a 2 L beaker. After dispersing for 5 minutes, the mixture was placed in a 5 L autoclave, purged with nitrogen, and polymerized at 83 ° C. for 90 minutes and further at 100 ° C. for 60 minutes. After polymerization, washing, dehydration, and drying were performed to obtain a bead polymer.
The obtained polymer particles had an average particle diameter of 250 μm, and silicone resin particles were uniformly dispersed in the particles. The MFR was 5.2 (g / 10 min).
[0020]
Example 2
Polymer particles were obtained in the same manner as in Example 1 except that polystyrene crosslinked particles (manufactured by Sumitomo Chemical Co., Ltd .: Fine Pearl, average particle size 6.0 μm) were used as the fine polymer particles instead of the silicone resin particles. .
The obtained polymer particles had an average particle diameter of 260 μm, and polystyrene cross-linked particles were uniformly dispersed in the particles. The MFR was 5.1 (g / 10 min).
[0021]
Comparative Example 1
The same procedure as in Example 1 was conducted except that lauryl mercaptan was not used as the chain transfer agent.
The obtained polymer particles had an average particle diameter of 250 μm, and silicone resin particles were uniformly dispersed in the particles. However, the MFR of the polymer was not measurable because the molten resin did not flow out under the predetermined conditions.

Claims (5)

The MFR is 1 to 50 (g / 10 min), a method for producing a masterbatch comprising polymer particles in which fine polymer particles are dispersed ,
A method for producing a masterbatch, wherein a polymerizable vinyl monomer and fine polymer particles insoluble in the monomer are dispersed in an aqueous system, and suspension polymerization is performed in the presence of a chain transfer agent. 2. The production method according to claim 1, wherein the fine polymer particles in the polymer particles are 0.01 to 1% by weight. The method according to claim 1, wherein the average particle size of the fine polymer particles is 0.1 to 50 µm. The process according to claim 1, wherein the chain transfer agent mercaptans. The production method according to claim 1 , wherein the amount of the chain transfer agent used is 0.01 to 3 parts by weight with respect to 100 parts by weight of the polymerizable vinyl monomer.