JPH06166792A - Plate for vacuum forming - Google Patents

Abstract

PURPOSE:To obtain a plate for vacuum forming excellent in flexural elastic modulus, impact resistance, vacuum formability and surface smoothness. CONSTITUTION:This plate for vacuum forming is formed from a resin composition composed of 100 pts.wt. graft copolymer prepared by graft copolymerization of 96-70wt.% vinyl chloride monomer with 4-30wt.% alkyl (meth)acrylate polymer consisting essentially of an alkyl (meth)acrylate monomer having <=-20 deg.C second order transition point of a homopolymer thereof and having 50-95wt.% crosslinking ratio and 2-15 pts.wt. acrylic processing aid having 1000000-5000000 weight-average molecular weight.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum forming plate excellent in flexural modulus and surface smoothness.

[0002]

2. Description of the Related Art Conventionally, a vinyl chloride resin vacuum forming plate has not only excellent vacuum forming performance, but also many excellent features such as impact resistance, weather resistance and water resistance. Therefore, it is used in a wide range of applications.

As the above-mentioned vacuum forming plate, a composition comprising a vinyl chloride resin, an acrylic rubber-based reinforcing agent, and an acrylic rubber-based processing aid (JP-A-60-161449) is disclosed.

However, in order to obtain a plate excellent in vacuum formability from the above composition, it is necessary to add a large amount of an acrylic reinforcing agent and an acrylic processing aid to the composition, and the obtained plate has a bending elasticity. There was a problem that the rate was low.

Further, the addition of a large amount of the composition causes the composition to have a high viscosity in a molten state, resulting in poor moldability, and thus there is a problem that the surface smoothness of the extruded plate is impaired.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object thereof is for vacuum forming which is excellent in flexural modulus, impact resistance, vacuum formability and surface smoothness. To provide the plate.

[0007]

The alkyl (meth) acrylate polymer used in the present invention is mainly composed of an alkyl (meth) acrylate monomer having a second-order transition point of a homopolymer of -20 ° C or less and a crosslinking rate. Is a polymer of 50 to 95% by weight.

The alkyl (meth) acrylate monomer is not particularly limited as long as the secondary transition point is -20 ° C or lower, and examples of such an alkyl (meth) acrylate monomer include ethyl acrylate and n-propyl acrylate. , N-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, n-octyl methacrylate, n-decyl methacrylate, n
-Dodecyl methacrylate and the like are used, and one or more of these are used.

In the alkyl (meth) acrylate polymer, if necessary, the alkyl (meth) acrylate monomer may be copolymerized with another monomer copolymerizable with the alkyl (meth) acrylate monomer.

Other monomers copolymerizable with the above alkyl (meth) acrylate include, for example, styrene and α.
-Styrene-based monomers such as methylstyrene; acrylonitrile; alkyl (meth) acrylate monomers having a secondary transition point higher than -20 ° C, and the like, and one or more of these monomers are used.

Examples of the alkyl (meth) acrylate monomer having a second-order transition point higher than -20 ° C. include, for example, methyl acrylate, isopropyl acrylate, t-butyl acrylate, n-tetradecyl acrylate, n.
-Hexadecyl acrylate, lauryl acrylate,
Cyclohexyl acrylate, methyl methacrylate,
Ethyl methacrylate, n-hexyl methacrylate,
Examples include n-tetradecyl methacrylate and n-butyl acrylate.

The content of the other monomer in the above-mentioned alkyl (meth) acrylate polymer is preferably 10% by weight or less because the impact resistance decreases as the content increases.

When the cross-linking ratio of the above alkyl (meth) acrylate polymer is small, the impact strength of the vacuum forming plate is insufficient, and when it is large, the workability of the plate is deteriorated and the surface smoothness is deteriorated. It is limited to 50 to 95% by weight.

The cross-linking ratio is obtained by dissolving 1 g of the alkyl (meth) acrylate polymer in 100 ml of THF at 30 ° C. for 7 hours and measuring the weight ratio of the insoluble portion.

In order to crosslink the above alkyl (meth) acrylate polymer, it is preferable to react a polyfunctional monomer. Examples of such a polyfunctional monomer include ethylene glycol diacrylate, diethylene glycol diacrylate and triethylene glycol. Examples thereof include diacrylate, ethylene glycol dimethacrylate, diallyl phthalate and diallyl malate.

In the present invention, the method for obtaining the crosslinked alkyl (meth) acrylate polymer is not particularly limited, and examples thereof include emulsion polymerization method and suspension polymerization method. Is preferred.

The additives used in the emulsion polymerization are not particularly limited and include, for example, a dispersion emulsifier, a polymerization initiator and a pH.
Examples include regulators and antioxidants.

Examples of the dispersant emulsifier include anionic surfactants, nonionic surfactants, partially saponified polyvinyl alcohol, cellulosic dispersants, gelatin, and the like. Polymerization initiators include, for example, persulfuric acid. Examples thereof include water-soluble polymerization initiators such as potassium, ammonium persulfate, and hydrogen peroxide; oil-soluble polymerization initiators such as benzoyl peroxide and lauroyl peroxide.

The graft polymer used in the present invention is a polymer in which a vinyl chloride monomer is graft-polymerized to the above-mentioned alkyl (meth) acrylate polymer.

Generally, when a vinyl chloride homopolymer is used for vacuum forming, its viscosity average degree of polymerization is from 600 to 600.
1400 is preferred. Therefore, when the vinyl chloride monomer is graft-polymerized, the calibration curve of the viscosity average polymerization degree prepared from the vinyl chloride homopolymer is used, and the viscosity average polymerization is 6
It is preferable to carry out the polymerization under the condition that the reaction amount is from 00 to 1400.

The vinyl chloride monomer may be copolymerized with a monomer other than vinyl chloride together with the vinyl chloride monomer as long as the characteristics of vinyl chloride are not impaired. Examples of such a monomer include Α-olefins such as ethylene and propylene; vinyl esters such as vinyl acetate and vinyl stearate; N-phenylmaleimide,
N-substituted maleimides such as N-cyclohexylmaleimide; vinylidene chloride and the like, and one or two of these.
More than one seed is used.

In the copolymer of the vinyl chloride monomer and a monomer other than vinyl chloride, the content of the monomer is preferably 20% by weight or less.

In the present invention, when the amount of the alkyl (meth) acrylate polymer in the graft polymer is small, the impact strength of the obtained plate is insufficient, and when it is large, the flexural modulus of the plate is lowered. The alkyl (meth) acrylate polymer is limited to 4 to 30% by weight, preferably 6 to 20% by weight.

As the polymerization method for graft-polymerizing vinyl chloride on the above alkyl (meth) acrylate polymer, for example, emulsion polymerization method, suspension polymerization method, solution polymerization method, etc. can be used, but suspension polymerization method Is preferred.

In the above suspension polymerization method, as a dispersion emulsifier,
Examples include anionic surfactants, nonionic surfactants, partially saponified polyvinyl alcohol, and cellulose-based dispersants. Examples of the polymerization initiator include benzoyl peroxide, lauroyl peroxide, and 2
-Peroxides such as ethylhexyl peroxydicarbonate; 2,2-azobisisobutyronitrile,
Examples thereof include azo compounds such as 2,2-azobis-2,4-dimethylvaleronitrile.

In the above suspension polymerization method, if necessary, a pH adjusting agent, a polymerization degree adjusting agent, an antioxidant, etc. may be added.

The acrylic processing aid used in the present invention is a methyl methacrylate homopolymer or a copolymer of methyl methacrylate and another monomer. Examples of commercially available products of the above-mentioned acrylic processing aids include "Metablene P-551A" and "Metablene P-5" manufactured by Mitsubishi Rayon Co., Ltd.
30A "," Metablene P-501A "," Acryloid K-175 "," Acryloid K-120ND "," Acryloid K-120N "manufactured by Rohm and Haas.
"Acryloid K-125" etc. are mentioned.

In the present invention, when the molecular weight of the acrylic processing aid is small, the vacuum forming property of the obtained plate is poor, and when it is large, the surface smoothness of the plate is deteriorated. Therefore, the molecular weight is 1,000,000 in terms of weight average molecular weight. Limited to ~ 5 million.

The resin composition used in the present invention contains the above graft polymer and the above acrylic processing aid. In the above resin composition, when the amount of the acrylic processing aid used is small, the vacuum moldability of the plate is poor, and when it is too large, the surface smoothness of the plate is deteriorated.
The acrylic processing aid is limited to 2 to 15 parts by weight, preferably 3 to 12 parts by weight, based on 00 parts by weight.

If necessary, a heat stabilizer, a stabilizing aid, a lubricant, a processing aid, an antioxidant, an ultraviolet absorber, a light stabilizer filler, a pigment and the like are added to the above resin composition. Good.

Examples of the heat stabilizer include organic materials such as dibutyltin mercapto, dioctyltin mercapto, dimethyltin mercapto, dibutyltin malate, dibutyltin malate polymer, dioctyltin malate, dioctyltin malate polymer and dibutyltin laurate. Tin stabilizers; lead-based stabilizers such as tribasic lead sulfate, dibasic lead phosphite, and lead stearate; calcium-zinc stabilizers; barium-zinc stabilizers; barium-cadmium stabilizers and the like. To be

Examples of the stabilizing aid include epoxidized soybean oil and phosphoric acid ester, and examples of the lubricant include paraffin wax, polyethylene wax, stearic acid, stearyl alcohol and butyl stearate. Can be mentioned.

Examples of the processing aid include acrylic processing aids having a weight average molecular weight of less than 1,000,000,
Examples of the filler include fillers such as calcium carbonate and talc.

A small amount of a plasticizer such as di-2-ethylhexyl phthalate, dibutyl phthalate or di-2-ethylhexyl adipate may be added to the above resin composition in order to improve the processability of the plate. .

As a method of mixing the above resin composition,
Any method such as a hot blend method or a cold blend method may be used.
An extrusion molding method, a calendar molding method, a press molding method and the like can be mentioned.

[0036]

Embodiments of the present invention will be described below. (Examples 1 to 3 and Comparative Examples 1 to 6) 100 parts by weight of a vinyl chloride graft polymer having the composition shown in Table 1 was added with a predetermined amount of the acrylic processing aid shown in Table 1 ("Metablen" manufactured by Mitsubishi Rayon Co., Ltd.). )), As an additive, 0.5 parts by weight of dibutyltin malate polymer (“BM (N)” manufactured by Sankyo Machine Synthesis Co., Ltd.), dibutyltin mercapto (“JF-10” manufactured by Sankyo Machine Synthesis Co., Ltd.)
B ") 2.5 parts by weight, stearic acid (Kawaken Fine Chemicals" F-3 ") 1.5 parts by weight, polyethylene wax (Mitsui Petrochemical" 4202E ") 0.5 parts by weight and steer. Calcium phosphate ("SC-1" manufactured by Sakai Chemical Industry Co., Ltd.
00 ") 0.5 parts by weight of a resin composition are uniformly mixed, and then a 50 mm twin-screw extruder is used to extrude a vacuum forming plate having a resin temperature of 190 ° C. and an extrusion rate of 50 kg / hr and a thickness of 3 mm. did. The following physical properties were measured using this vacuum forming plate as a sample, and the results are shown in Table 1.

(1) Izod impact strength Measured according to JIS K7110. (2) Vacuum Formability Using a vacuum forming machine (made by Fuse Vacuum Co., Ltd.), a processing temperature of 21
A 500 × 500 × 3 mm vacuum forming plate was vacuum formed at 0 ° C. using a cylindrical mold having a height of 90 mm and a diameter of 180 mm, and the obtained formed body was evaluated according to the following criteria. ◯: The size as the mold was obtained, Δ: The size of the corner portion was insufficient, and X: the shape as the mold was not obtained. (3) Surface smoothness The plate surface was visually observed and evaluated according to the following criteria. ○: No surface roughness, △: Some surface roughness,
X: There are many rough surfaces. (4) Flexural modulus It was measured according to JIS K7203.

(Comparative Example 7) 100 parts by weight of a vinyl chloride homopolymer having a viscosity average degree of polymerization of 800, 12 parts by weight of an acrylic rubber type reinforcing agent ("KM-334" manufactured by Rohm and Haas Co.) and a weight average molecular weight of 3. 1 x 10 ⁶ acrylic processing aid ("Metablen P530A" manufactured by Mitsubishi Rayon Co., Ltd.) 5
A vacuum molding plate was extrusion-molded in the same manner as in Example 1 from the resin composition in which the same additives as in Example 1 were added to parts by weight. Physical properties of the obtained plate were measured in the same manner as in Example 1, and the results are shown in Table 1.

[0039]

[Table 1]

[0040]

EFFECT OF THE INVENTION The vacuum forming plate of the present invention is as described above, and has vacuum forming property, impact resistance, flexural modulus,
It has excellent surface smoothness and is suitable for use in housings for building materials, vehicle parts, audio / communication equipment, office automation equipment, etc.

Claims (1)

[Claims] 1. An alkyl (meth) which is mainly composed of an alkyl (meth) acrylate monomer having a homopolymer having a second-order transition temperature of -20 ° C. or lower and a crosslinking rate of 50 to 95% by weight.
100 parts by weight of a graft polymer in which 96 to 70% by weight of a vinyl chloride monomer is graft-polymerized to 4 to 30% by weight of an acrylate polymer, and a weight average molecular weight of 1,000,000 to 5
A plate for vacuum forming, which is formed from a resin composition containing 2 to 15 parts by weight of an acrylic processing aid of 2,000,000.