JPH085928B2 - Method for producing vinyl polymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a method for rapidly polymerizing vinyl monomers with a novel polymerization initiator system.

<Prior Art> Conventionally, polymerization of a monomer such as methyl methacrylate having a polymerizable unsaturated bond in a molecule by a radical polymerization initiator, and further a polymerization method using a redox polymerization initiator are various methods. It has been known.

The benzoyl peroxide / amine combination, for example, is a redox initiator which has been known for a long time.

In addition, the method described in Japanese Examined Patent Publication No. 41-21037 is a polymerization method in which discoloration is improved by using a methyl methacrylate monomer with a hemiperester maleate and an amine at 40 ° C. or 60 ° C. for 20 minutes or more. It is shown.

Further, in JP-B-45-4630, methyl methacrylate syrup is polymerized at 40 ° C. in the presence of a specific basic metal compound such as maleic acid hemiperester and calcium hydroxide and further mercaptan, and curing time is set. An improved method of is shown.

Similarly, in Japanese Examined Patent Publication No. 50-22586, methyl methacrylate syrup in the presence of a hydrate inorganic filler, maleic acid hemiperester and a specific basic metal compound, water,
A method of polymerizing by the use of mercaptan has been shown, in which the presence of water in particular is said to accelerate the curing.

Further, also in JP-A-61-141710, as a method for curing methyl methacrylate at room temperature in a short time, a specific organic peroxide, an organic amine or a soluble metal salt in the presence of a specific metal salt is used. A polymerization process with an initiator system consisting of

<Problems to be Solved by the Invention> However, such conventional redox polymerization initiators were developed mainly for the purpose of shortening the polymerization-curing time at low temperatures, and the polymerization obtained by polymerization was used. There is a problem in practical use with regard to the performance of coalescence.

For example, according to British Patent No. 870191, a combination of a peroxide such as benzoyl peroxide and lauroyl peroxide and various amines increases the polymerization and curing rate at low temperature, but such a polymer is Deterioration easily occurs due to light and heat, and it easily turns yellow.

Further, in the methods of JP-B-41-21037, JP-B-45-4630 and JP-B-50-22586, the purpose is also to cure in a short time. This is a polymerization method carried out in the presence of a basic metal compound insoluble in the polymer, and the polymer becomes opaque.

Further, in the method disclosed in JP-A-61-141710, water and a solvent are used to solubilize the metal salt.

In such a polymer, water and a solvent remain as they are, and a large number of bubbles are generated in the polymer due to heat generation and heat generation due to polymerization, which is not suitable as a molded article, and the heat distortion temperature is lowered. Have.

As described above, the water, the solvent, the insoluble metal compound remaining in the polymer, and the residual monomer in the polymer bring about a great adverse effect in maintaining and exhibiting the original performance of the polymer.

<Means for Solving Problems> At least one monomer selected from a monomer having one acryloxy group or a methacryloxy group in the molecule and an aromatic vinyl compound is added to the following (A) and (B ),
In the absence of solvent, the initiator system consisting of (C) and (D)
A method for producing a vinyl-based polymer, which comprises polymerizing at 50 ° C to 150 ° C.

(A) Peroxyester (B) Mercaptans (C) Organic amine (D) Metals selected from tin, aluminum or antimony and acetylacetone, phenylacetylacetone, tris (dipivaloylmethanite), trispivaloyltrifluoro Acetonite, a metal complex with an organic compound selected from 2,2,6,6-tetramethyl-3,5-heptadione, and an organic compound containing at least one metal selected from the metal aryl compounds The at least one monomer selected from the monomer having one acryloxy group and methacryloxy group in the molecule and the aromatic vinyl compound used in the present invention includes (meth) acrylate and ethyl (meth) acrylate. Butyl (meth) acrylate, isopropyl (meth) acrylate, (meth) acrylate Acid isobornyl, bornyl (meth) acrylate, cyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, phenyl (meth) acrylate, benzyl (meth) acrylate, tribromophenyl (meth) acrylate, (Meta)
Acrylic esters and methacrylic acid esters with aliphatic alcohols having 1 to 25 carbon atoms such as furfuryl acrylate, alicyclic alcohols, heterocyclic alcohols, aromatic alcohols or phenols, halogen-containing aromatic ring alcohols or phenols: Or styrene, α-
Aromatic vinyl compounds such as methylstyrene, p-methylstyrene, p-chlorostyrene, p-bromostyrene:
Acrylic metal salts and methacrylic acid metal salts such as copper (meth) acrylate, neodymium (meth) acrylate and lead (meth) acrylate: unsaturated carboxylic acids such as acrylic acid and methacrylic acid: it can.

The selection of such a monomer depends on the performance to be possessed by the desired polymer.

For example, optical products such as lenses may be selected according to the required performance such as light transmittance, refractive index and heat resistance.

The monomers of the present invention can be used alone or in combination, and further other copolymerizable monomers can be used in combination.

Other copolymerizable monomers can be used in a range that does not hinder the performance of the polymer, but usually 50% to the total monomers.
It is used in the range of not more than wt%.

Further, in the present invention, in order to further improve the strength and chemical resistance of the molded product, a polyfunctional monomer having at least two polymerizable unsaturated carbon bonds in the molecule can be used.

Examples of such polyfunctional monomers include ethylene glycol (meth) acrylate, diethylene glycol di (meth) acrylate, and triethylene glycol di (meth) acrylate.
Ethylene glycol such as acrylate, tetraethylene glycol di (meth) acrylate, nonaethylene glycol di (meth) acrylate, tetradecaethylene glycol di (meth) acrylate, or the oligomer thereof is esterified at both terminal hydroxyl groups with acrylic acid or methacrylic acid. Thing; neopentyl glycol di (meta)
Acrylate, hexanediol di (meth) acrylate, butanediol di (meth) acrylate, or other dihydric alcohol with the hydroxyl group esterified with acrylic acid or methacrylic acid; bisphenol A or an alkylene oxide adduct of bisphenol A or Those in which the hydroxyl groups at both ends of these halogen-substituted compounds are esterified with acrylic acid or methacrylic acid; those with polyhydric alcohols such as trimethylolpropane and pentaerythritol esterified with acrylic acid or methacrylic acid;
And those obtained by ring-opening addition of an epoxy group of glycidyl acrylate or glycidyl methacrylate to the terminal hydroxyl groups of these dihydric alcohols or polyhydric alcohols; succinic acid, adipic acid, terephthalic acid, phthalic acid or halogen substitution products thereof. A basic acid or an alkylene oxide adduct thereof obtained by ring-opening addition of an epoxy group of glycidyl acrylate or glycidyl methacrylate; aryl methacrylate, divinylbenzene and the like.

Such a polyfunctional monomer can be used together with a monomer having one polymerizable unsaturated carbon bond or a copolymerizable monomer in the molecule described above, and can be used as a reactive raw material liquid in the present invention. Of these, it can be used within the range of 30% by weight or less.

If it exceeds 30% by weight, it becomes difficult to maintain the mechanical strength and transparency, and the polymerization tends to become non-uniform, which is not preferable.

The monomer used in the present invention can be used as it is, but it can be used as a liquid containing a part of the polymer in terms of polymerization curability and handleability.

The liquid containing a part of the polymer can be prepared by a known method such as a method of dissolving the polymer in a monomer or a method of prepolymerizing the monomer.

From the viewpoint of handling, the viscosity of the liquid is preferably 10 to 50,000 centipoise.

In the present invention, polymerization is carried out by using at least one organic compound containing a metal selected from peroxyester (A), mercaptans (B), amine (C) and tin, aluminum or antimony (D). Can be done in a short time.

Peroxyester is a peroxide having a peroxyester bond in the molecule and includes t-butylperoxyacetate, t-butylperoxypivalate, t-butylperoxybenzoate and t-butylmaleic acid hemiper. Examples thereof include esters, t-butyl fumaric acid hemiperesters, t-butylphthalic acid hemiperesters, t-butyl succinic acid hemiperesters, and di-t-butyl fumaric acid hemiperesters.

Among such peroxyesters, it is preferable to use a hemiperester which is a peroxyester having a free carboxylic acid in the molecule.

The peroxy ester (A) is used in an amount of 0.01 to 5 parts by weight based on 100 parts by weight of the monomers.

If it is less than 0.01 part by weight, the polymerization time will be long in practice, and if it exceeds 5 parts by weight, the effect of shortening the polymerization time will be small.

The mercaptans (B) used in the present invention are compounds having an SH group in the molecule,
Lauryl mercaptan, n-octyl mercaptan, α
-Ethylhexyl mercaptan, 2-mercaptopropionic acid, glycol dimercapto acetate, glycol dimercapto propionate, trimethylolpropane trismercapto propionate and the like can be mentioned.

The mercaptans, 0.0 with respect to 100 parts by weight of the monomers, 0.0
Use 1 to 1 part by weight.

If it is less than 0.01 part by weight, the polymerization time will be long in practice, and if it is used in excess of 1 part by weight, the effect of shortening the polymerization time will be small.

Further, as the amine (C) used in the present invention, any of primary, secondary, tertiary amine, quaternary ammonium chloride, alkanolamine, etc. can be used.
Examples of amines include n-octylamine, laurylamine, dibutylamine, tributylamine, N, N-dimethyl-p-toluidine, phenethyldibutylamine and the like.

The amine is used in an amount of 0.01 to 1 part by weight based on 100 parts by weight of the monomers.

If it is less than 0.01 part by weight, the polymerization time will be long in practice, and if it is used in excess of 1 part by weight, the effect of shortening the polymerization time will be small.

Further, the amine used in the present invention may be used as an inorganic acid such as hydrochloride.

Of these, amine hydrochloride is preferable because it has an effect of improving releasability.

Further, tin, aluminum, an organic compound containing a metal selected from antimony used in the present invention is soluble in monomers even without the presence of a solvent such as water or an organic solvent. The metal-containing organic compound is selected from acetylacetone, phenylacetylacetone, tris (dipivaloylmethanite), trispivaloyltrifluoroacetonite, and 2,2,6,6-tetramethyl-3,5-heptadione. It is an aryl compound of a metal such as a metal complex with an organic compound or a triphenyl compound.

The organic compound containing the metal is used in an amount of 0.001 to 1 part by weight based on 100 parts by weight of the monomers.

If it is less than 0.001 part by weight, the polymerization time will be long practically,
Further, even if more than 1 part by weight is used, there is little effect in shortening the polymerization time.

To polymerize the monomers of the present invention with those of the initiator system,
A usual polymerization method for polymerizing a vinyl-based monomer can be applied.

Of these, bulk polymerization is suitable as the polymerization method of the present invention, and cast polymerization also exerts its characteristics in bulk polymerization.

In cast polymerization, the initiator system may be mixed and dissolved in the monomers and then injected into the mold, and then the temperature may be raised to polymerize and cure.

Since the polymerization initiator system of the present invention has a high polymerization activity, it is desirable to carry out the polymerization in the polymerization site as early as possible if mixed with the monomers.

Among the initiator systems, peroxyester (A) and mercaptans (B) were separately dissolved in monomers, and after mixing both, immediately poured into a heated mold and heated. It can also be cured in a closed mold in a short time.

The amine (C) and the metal-containing organic compound (D) may be dissolved in either direction.

The polymerization temperature in the present invention can be in the range of 50 to 150 ° C., and further, it is preferable to perform the polymerization at 60 to 120 ° C. Further, after the polymerization and curing as necessary, heat treatment at 100 to 150 ° C. You can also

At a temperature of less than 50 ° C, it takes a long time to exceed 10 minutes for polymerization and curing, and there are many residual monomers in the polymer,
Further, at a temperature above 150 ° C., decomposition due to heat generation is accompanied, and the amount of residual monomer in the polymer increases, which is not preferable.

Further, it is also possible to apply pressure when polymerizing and curing in the mold.

This pressure is about 1 to 100 kg / cm ² .

According to the method of the present invention, the polymerization time can be as short as 5 minutes or less.

Further, the monomer used in the present invention may be used in combination with a light stabilizer, a heat stabilizer, an inorganic filler, a colorant, a release agent, a lubricant, a foaming agent and the like, if necessary.

<Effects of the Invention> According to the present invention, the polymerization time is extremely short, and the obtained polymer has few monomers remaining inside, does not contain water or solvent, has excellent heat resistance and transparency, and has few bubbles. A good product is obtained.

Particularly in the case of a polymer that is required to have transparency, a polymer having excellent heat resistance, light resistance, chemical resistance, strength, etc. in addition to transparency can be obtained and can be used for optical parts and the like.

According to the present invention, the obtained product can also be applied to cast molding in which a molded product is polymerized in a mold, reaction injection molding, can be polymerized in an industrially practicable time, and has excellent mold releasability. Therefore, it can be applied to the molding of large-sized molded products and thin-walled molded products.

Examples of such products include Fresnel lenses, screens for video projectors, general-purpose lenses, mirrors, optical elements such as optical disks: sunroofs, windows, grills, lamp covers and other automobile parts: wash basins,
Building materials such as table tops, counter tops, doors, water tanks, bathtubs, furniture: etc.

<Example> Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited thereto.

The polymerization time in the examples means the time at which the polymerization peak temperature after injection into the mold was shown.

The residual monomer was obtained by measuring the amount of the monomer contained in the molded article by laser Raman spectroscopy.

 The appearance was visually observed with the molded product.

The heat resistance was observed by naked eyes such as coloring and foaming after heating the molded product at 150 ° C. for 30 minutes.

Heat distortion temperature is ASTM D-648, haze value is ASTM D-100
It measured based on 3.

Examples 1 to 4 and Comparative Examples 1 to 4 (Production of original syrup) 700 g of methyl methacrylate and 2 g of a glass flask in a glass flask.
Methyl methacrylate resin (SUMIPEX B MH, Sumitomo
300g of Gaku Kogyo Co., Ltd. was added and dissolved by stirring for 24 hours.
I got the raw syrup.

(Adjustment of casting syrup) Put 500 g of the above original syrup in a glass flask,
To this, 5 g of glycol dimercaptoacetate, 0.5 g of trioctylamine hydrochloride and 2.5 g of acetylacetone tin were added, and each of the polymerization initiators shown in Table 1 were further added and mixed and dissolved to obtain a uniform syrup.

(Polymerization Molding) Using these syrups, liquid was poured into a mold having a space volume of 150 × 150 × 3 mm, sealed, and then heated to 85 ° C. for polymerization.

After 30 seconds from the start of heating, the liquid in the mold becomes about 85 ° C,
The peak temperature due to the heat of reaction was shown in the polymerization time shown in Table 1.

Immediately after the temperature of the polymer in the mold reached 85 ° C. again, the frame was opened and the polymer was taken out from the mold.

The results of measuring the physical properties of the obtained polymer are shown in Table 1.

Examples 5-7 and Comparative Examples 5-8 Produced in the same manner as in Example 1, 450 g of raw syrup, 25 g of tetraethylene glycol dimethacrylate, 5 g of mono-t-butyl maleic acid hemiperoxy ester as a polymerization initiator, and pentaerythritol. 5 g of tetrakis (mercaptopropionate), 0.5 g of dimethyloctylamine and 2.5 g of the metal-containing organic compound shown in Table 2 were added and mixed with stirring to obtain a syrup for injection.

This liquid injection syrup was cast in the same manner as in Example 1 and then polymerized and cured.

 The physical properties of the obtained polymerized molded product are shown in Table 2.

It is clear from Table 2 that the molded product of the present invention has excellent transparency.

Examples 8 to 13 and Comparative Example 9 As shown in Table 3, t-butyl maleic acid hemiperoxy ester (A) and n-octyl mercaptan (B) were added to 500 g of the raw syrup produced in the same manner as in Example 1. , Dimethyloctylamine (Example 13 only, its hydrochloride)
(C) and a predetermined amount of acetylacetone-tin (D) were added to adjust the syrup.

Using each of the obtained syrups, polymerization was carried out in the same manner as in Example 1 to obtain a molded product.

The results of measuring the physical properties of the obtained molded product are shown in Table 3.

Example 14 (Preparation of syrup A) To 475 g of the raw syrup prepared in the same manner as in Example 1, 25 g of neopentyl glycol dimethacrylate, 10 g of mono-t-butyl maleic acid hemiperoxy ester, 1.5 g of dimethyldecylamine hydrochloride and acetylacetone were prepared. -Tin 4g was added, mixed and dissolved to obtain a uniform syrup A.

(Preparation of syrup B) To 500 g of the raw syrup prepared in Example 1, 10 g of glycol dimercaptoacetate was added and mixed and dissolved to obtain a uniform syrup B.

The obtained syrups A and B were usable after being stored in an atmosphere of 40 ° C., even after 1 day, without increasing in viscosity.

95g of syrup A and 90g of syrup B are mixed at a room temperature with a constant rate pump of the same discharge amount into a dynamic mixing type mixer with an average residence time of 3 seconds.
It was poured into a mold having the shape of a disc having a diameter of 300 mm and a thickness of 1.2 mm, which was adjusted to the temperature.

After the pouring, the inside of the mold was pressurized to 10 kg / cm ² to carry out polymerization.

A polymerization peak temperature was exhibited 2 minutes after the pouring was completed, and the obtained molded product was free from bubbles, sink marks and the like and was excellent in transparency.

The molded product had a haze value of 1.0%, a heat distortion temperature of 92 ° C, and a residual monomer content of 2%.

Examples 15 to 17 and Comparative Examples 10 to 11 In the same manner as in Example 1, polymerization molding was carried out at the temperatures of the molds shown in Table 4.

Table 4 shows each polymerization time and the residual monomer in the molded product.

In this example, the molded product obtained had a small amount of residual monomers, and was excellent in heat resistance and transparency.

Examples 18 to 26 (Preparation of syrup) The monomers shown in Table 5 were put in a 2 l glass flask,
Add 0.1 g of azobisisobutyronitrile and dissolve, then 80 ℃
It was heated to and polymerized.

When the viscosity reaches about 1 poise, cool to stop the polymerization,
A uniform prepolymerized syrup was obtained.

(Compounding) After the pre-added monomers shown in Table 5 were mixed and dissolved in the obtained prepolymerized syrup, mono-t was used as a polymerization initiator.
15 g of butyl maleic acid hemiperoxy ester, 5 g of trimethylolpropane trimercaptoacetate, 5 g of trioctylamine hydrochloride and 5 g of acetylacetone-tin were mixed and dissolved to prepare a uniform syrup.

(Polymerization molding and evaluation) Using the respective syrups prepared as described above, a flat plate molded article of 150 x 150 x 3 mm was polymerized in the same manner as in Example 1 to obtain.

The results of measuring the physical properties of the obtained molded product are shown in Table 5.

Examples 27 to 29 (Preparation of syrup) A preliminary syrup was obtained in the same manner as in Example 18 except that the monomers shown in Table 6 were used.

(Compounding) To the obtained preliminary syrup, the same polymerization initiator as in Example 18 was added to obtain a uniform syrup.

(Polymerization molding and evaluation) It carried out like Example 18.

 The results are shown in Table 6.

Claims (2)

[Claims] 1. A monomer having one acryloxy group or a methacryloxy group in the molecule and at least one monomer selected from aromatic vinyl compounds, the following (A),
A method for producing a vinyl polymer, which comprises polymerizing at 50 ° C. to 150 ° C. in the absence of a solvent with an initiator system comprising (B), (C) and (D). (A) Peroxyester (B) Mercaptans (C) Organic amine (D) Metals selected from tin, aluminum or antimony and acetylacetone, phenylacetylacetone, tris (dipivaloylmethanite), trispivaloyltrifluoro Metal complex with an organic compound selected from cetonite and 2,2,6,6-tetramethyl-3,5-heptadione, and an organic compound containing at least one metal selected from the metal aryl compounds 2. The initiator system is based on 100 parts by weight of monomers,
0.01 to 5 parts by weight of (A) peroxyester, 0.01 to 1 part by weight of (B) mercaptans, and (C) of 0.
01 to 1 part by weight, (D) metal-containing organic compound is 0.00
The manufacturing method according to claim 1, wherein the amount is 01 to 1 part by weight.