JPH0318665B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention has a boiling n-heptane insoluble content (II) of 30% or more and a melt flow index of 230%.
℃, Amount extruded in 10 minutes (MFI) 0.1~500g/
Polypropylene-vinyl chloride graft copolymer 100 with a vinyl chloride content of 30 to 90% by weight, produced by graft polymerization in the presence of polypropylene for 10 min in a state in which vinyl chloride monomer is substantially absent as a liquid phase. The present invention relates to a vinyl chloride resin composition imparted with rubber-like elasticity by adding 30 to 200 parts by weight of a plasticizer. Polypropylene as used herein means a propylene homopolymer or a copolymer with olefin. Soft vinyl chloride resin is a resin with well-balanced chemical and physical properties, and is used in a wide range of applications. However, in applications such as hoses, packing, electric wires, boot soles, leather, films, and industrial parts for automobiles, it is required to further improve the rubber properties. As a method to improve rubber properties,
The following two methods are known. That is, (1) a method using a highly polymerized vinyl chloride resin as a base resin, and (2) a method using a copolymer or blend of vinyl chloride. However, none of these methods can be said to be satisfactory. Regarding method (1), the physical properties are good, but
There is a problem with processability, and with method (2), there is a problem with the compatibility between the vinyl chloride resin and the elastic material.
The physical properties tend to deteriorate, and satisfactory results have not yet been obtained. The present inventors have achieved excellent rubber properties by adding a plasticizer to a polypropylene-vinyl chloride graft copolymer obtained by graft polymerizing vinyl chloride monomers by a specific method in the presence of specific polypropylene. The present inventors have discovered that a material with excellent workability can be obtained, and have thus arrived at the present invention. Graft polymerization of vinyl chloride is a known method for modifying PVC. For example, graft copolymers of vinyl chloride monomers having an ethylene-vinyl acetate copolymer or the like as a backbone are known for improving impact strength. Graft copolymers are also available as unplasticized soft vinyl chloride resins intended to replace liquid plasticizers in order to improve the plasticizer migration of soft vinyl chloride resins. As described above, graft copolymers of vinyl chloride have conventionally been used for purposes such as improving impact resistance and making plastic materials softer. Furthermore, grafting of polypropylene has rarely been carried out in the past. This is because it is difficult to dissolve polypropylene in vinyl chloride monomer, and it is difficult to obtain it as a product using conventional grafting methods. The polypropylene-vinyl chloride graft copolymer has II of 30% or more and MFI of 0.1 to 500 g/
Add an aqueous medium, an oil-soluble initiator, and if necessary a dispersant or an inert organic solvent to polypropylene for 10 min (pressure of vinyl chloride monomer in the polymerization vessel)/
(saturation pressure of vinyl chloride monomer) ratio 0.4~0.99
It is produced by polymerizing while charging vinyl chloride monomer to maintain the
Polypropylene with vinyl chloride content of 30-90% by weight
The effects of the present invention can only be achieved by using a vinyl chloride graft copolymer. The present invention will be explained in detail below. In other words, the present invention has II of 30% or more and MFI of
0.1~500g/10min polypropylene with water medium,
Add an oil-soluble initiator and, if necessary, a dispersant or an inert organic solvent to maintain the ratio of (pressure of vinyl chloride monomer in the polymerization vessel)/(saturation pressure of vinyl chloride monomer) at 0.4 to 0.99. A rubber made by adding 30 to 200 parts by weight of a plasticizer to 100 parts by weight of a vinyl chloride graft copolymer having a vinyl chloride content of 30 to 90% by weight, which is produced by polymerizing while charging a vinyl chloride monomer so as to This is a resin composition characterized by having shape elasticity. A vinyl chloride graft copolymer polymerized in such a state has a high grafting rate and a large amount of molecular chain entanglement, and is expected to exhibit performance different from conventional copolymers. When a hard polymer is selected as the backbone polymer and a plasticizer is added to the vinyl chloride graft copolymer that is efficiently graft-polymerized with vinyl chloride using this polymerization method, the backbone that cannot absorb the plasticizer into the softened vinyl chloride resin It is thought that the polymer acts as a type of crosslinking point, resulting in the development of rubber elasticity. In the polypropylene-vinyl chloride graft copolymer used in the present invention, the polypropylene is
It is desirable that II is 30% or more and MFI is 0.1 to 500 g/10 min. When II is lower than 30%, mechanical strength decreases. Also, when MFI is lower than 0.1g/10min, workability decreases and MFI is 500g/10min.
When it is higher, the mechanical strength decreases significantly. The vinyl chloride content in the polypropylene-vinyl chloride graft copolymer is preferably in the range of 30 to 90% by weight. When the vinyl chloride content is lower than 30% by weight, the mechanical strength decreases, and the graft copolymer with a vinyl chloride content higher than 90% by weight has a long polymerization time.
Poor productivity. In the graft polymerization method, the ratio of (pressure of vinyl chloride monomer in the polymerization vessel)/(saturation pressure of vinyl chloride monomer) is preferably in the range of 0.4 to 0.99. When it exceeds 0.99, homopolymer formation is significant, and when it is less than 0.4, the polymerization rate decreases, which is not preferable. The oil-soluble initiator used in this polymerization method is 2,
2'-azobis-2,4-dimethylvaleronitrile, 2,2'-azobis-4-methoxy-2,4-
Azo compounds such as dimethylvaleronitrile and 2,2'-azobisisobutyronitrile, peroxides such as lauroyl peroxide, benzoyl peroxide, t-butyl peroxypivalate, t-butyl peroxyneodecanate, peroxydicarbonates such as di-isopropyl peroxydicarbonate, di-sec-butyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate,
Flowable yellow peroxides such as acetylcyclohexylsulfonyl peroxide and acetyl-2-ethylhexylsulfonyl peroxide can be used alone or in combination. In this polymerization method, a dispersant may or may not be used, but if used, the amount should be determined relative to the aqueous medium.
0.15% by weight or less is used, and the type of dispersant may be any known dispersant, such as cellulose derivatives such as methylcellulose, ethylcellulose, propylcellulose, hydroxyethylcellulose, hydroxymethylcellulose, partially saponified polyvinyl alcohol, polyacrylic acid, maleic anhydride. Acids, synthetic polymers such as vinyl ether copolymers, esters such as propylene glycol fatty acid esters, glycerin fatty acid esters, sucrose acid esters, sorbitan acid esters, etc. can be used alone or in combination. The polymerization temperature can be selected within the range of 30 to 80°C. If the polymerization temperature is high, the degree of polymerization decreases, causing problems in mechanical properties. If the polymerization temperature is low, mechanical strength will improve, but processability will decrease. Moreover, the polymerization time is long and the productivity is poor. The plasticizer used in the composition of the present invention is not particularly limited, and includes, for example, phthalic acid esters such as dibutyl phthalate and dioctyl phthalate, dibasic acid esters such as dioctyl adipate and dioctyl sebacate, other phosphoric acid esters, and polyhydric alcohols. and derivatives thereof, epoxy fatty acid esters, chlorinated paraffins, polyesters, polyethers, etc. are used. The amount to be used may be selected depending on the purpose of use, but if it exceeds 200 parts by weight, it will be difficult to dry up and cause difficulties in molding. Further, fillers, various modifiers, various additives, etc. may be added to the composition of the present invention as necessary. Fillers include calcium carbonate, barium sulfate, talc, clay, mica, silica, aluminum hydroxide, magnesium hydroxide, silicates,
Examples include carbon black, and the amount added is 100 parts by weight per 100 parts by weight of the vinyl chloride graft copolymer.
Parts by weight or less are used. In addition, pigments, heat stabilizers, flame retardants, ultraviolet absorbers, lubricants, antistatic agents,
Various additive amounts such as antifogging agents may be added. Next, as a method for producing the composition of the present invention, the composition is uniformly mixed using a conventionally known method using a super mixer, a Henschel mixer, etc., and then a kneading machine such as a roll mill, a Banbury mixer, a kneading extruder, etc. It is heated, kneaded, and molded into a shape suitable for each purpose. The polypropylene-vinyl chloride graft copolymer composition of the present invention satisfies the physical properties required for rubber properties in terms of mechanical strength, compression set and permanent elongation other than impact modulus, and can be used in hoses, packing, electric wires, etc. It is an industrially useful composition that can be used for shoe soles, boots, leather, films, automobile industrial parts, etc. Next, the present invention will be specifically explained with reference to examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. Example 1 (Production method of polypropylene-vinyl chloride graft copolymer) 2. In an autoclave, 600 g of pure water, II 86.5%,
100g of powdered polypropylene with MFI2g/10min,
After charging 0.4 g of a mineral spirit solution of a peroxide polymerization initiator and repeating degassing and nitrogen substitution twice, the pressure was reduced and the temperature was reduced (pressure of vinyl chloride monomer in the polymerization vessel)/( Polymerization was carried out at 40° C. while maintaining the ratio of (saturation pressure of vinyl chloride monomer) at 0.96. Polymerization was completed in 13 hours, unreacted monomers were purged, and the resulting powdery polymer was taken out and dehydrated and dried. The vinyl chloride content was determined by chlorine analysis and was 72%. Yield: 370 g (Composition) To 100 parts by weight of the polypropylene-vinyl chloride graft copolymer thus obtained, 4 parts by weight of a tin-based stabilizer were thoroughly mixed in a super mixer. The mixture was heated in a heated roll mill at 150°C for 15 minutes.
Plasticizer (DOP: dioctyl phthalate)
It was kneaded with 70 parts by weight. The obtained sheet was press-molded, and various physical properties were measured in the following manner. Hardness: JIS K6301 (value after 10 seconds) Tensile properties: JIS K6723 Impact modulus: JIS K6301 Melt viscosity: Koka type flow tester (nozzle 1φ)
×10mm, 180℃) η=γ/γ〓 (Value calculated from τ value of γ〓=10 ² sec ^-1 ) As a result, hardness is 75, rebound modulus is 28%, melt viscosity is
A composition with excellent rubber-like elasticity of 0.46×10 ⁴ poise and low melt viscosity was obtained. Example 2 (Production method of polypropylene-vinyl chloride graft copolymer) Polymerization was carried out in accordance with Example 1 except that the polymerization time was changed to 7 hours. Vinyl chloride content is 63% and yield is 280
It was hot at g. (Composition) Example 1 was followed. Example 3 (Production method of polypropylene-vinyl chloride graft copolymer) Polymerization was carried out according to Example 1 except that the polymerization time was changed to 3 hours, and 160 g of polymer with a vinyl chloride content of 37% was obtained.
Obtained. (Composition) Example 1 was followed. Example 4 (Production method of polypropylene-vinyl chloride graft copolymer) Polymerization was carried out according to Example 1 except that the polymerization temperature was 60°C and the polymerization time was 5 hours, and 360 g of a polymer with a vinyl chloride content of 75% was obtained. Ta. (Composition) Example 1 was followed. Example 5 (Method for producing polypropylene-vinyl chloride graft copolymer) Polymerization temperature was 60°C, and the ratio of vinyl chloride monomer pressure/vinyl chloride monomer saturation pressure in the polymerization vessel was 0.76.
Polymerization was carried out according to Example 1 except that the polymerization time was changed to 11 hours. 290 g of a polymer having a vinyl chloride content of 66% was obtained. (Composition) Example 1 was followed. Example 6 (Production method of polypropylene-vinyl chloride graft copolymer) Polymerization was carried out according to Example 4, except that powdered polypropylene with II 58% and MFI 6.0 g/10 min was used as the raw material, and the polymerization time was 7 hours. , vinyl chloride content 72%
350g of polymer was obtained. (Composition) Example 1 was followed. Example 7 (Production method of polypropylene-vinyl chloride graft copolymer) 1 g of partially saponified polyvinyl alcohol in the polymerization system
was added and the polymerization time was changed to 10 hours. Polymerization was carried out in accordance with Example 1, and 335 g of a polymer containing 70% vinyl chloride was obtained. (Composition) Example 1 was followed. Example 8 (Production method of polypropylene-vinyl chloride graft copolymer) Polymerization was carried out according to Example 1 except that 100 g of methanol was added to the polymerization system and the polymerization time was 10 hours.
364 g of a polymer having a vinyl chloride content of 71% was obtained. (Composition) Example 1 was followed. Example 9 (Production method of polypropylene-vinyl chloride graft copolymer) Same as Example 1 except that 50 g of propylene-ethylene random copolymer with II 85% and MFI 7.8 g/10 min was used and the polymerization time was 8 hours. Thus, 186 g of a polymer having a vinyl chloride content of 73% was obtained. (Composition) Example 1 was followed. Example 10 (Method for producing polypropylene-vinyl chloride graft copolymer) Example 1 was followed except that a propylene-ethylene random copolymer with II 84% and MFI 1.8 g/10 min was used, and the polymerization time was 8 hours. The polymerization was conducted to obtain 365 g of a polymer having a vinyl chloride content of 73%. (Composition) Example 1 was followed. Example 11 (Production method of polypropylene-vinyl chloride graft copolymer) Example 1 was followed except that a propylene-ethylene random copolymer with II 95% and MFI 7.8 g/10 min was used and the polymerization time was 11 hours. 363 g of a polymer having a vinyl chloride content of 73% was obtained. (Composition) Example 1 was followed. Comparative Example 1 (Production method of polypropylene-vinyl chloride graft copolymer by suspension method) 2. 900 g of pure water, 100 g of powdered polypropylene, 8 g of partially saponified polyvinyl alcohol, and 300 g of vinyl chloride monomer were placed in an autoclave.
C. and stirred at high speed for 2 hours. After cooling to 40℃, add peroxide polymerization initiator to mineral spirit solution.
0.5 g was injected under pressure to start polymerization. After the polymerization was completed, unreacted monomers were collected, and the product was taken out and dehydrated and dried. 290 g of a polymer having a vinyl chloride content of 78% was obtained. (Composition) Example 1 was followed. Comparative Example 2 (Blend system of vinyl chloride homopolymer and polypropylene) 100 parts by weight of vinyl chloride homopolymer (:1300), II 86.5%, 30 parts by weight of powdered polypropylene with MFI 2.0 g/10 min, tin-based stabilizer 4 parts by weight and 70 parts by weight of DOP (dioctyl phthalate) as a plasticizer were added and mixed in a super mixer. The resulting mixture was kneaded at 150° C. for 15 minutes using a heated roll mill, but a uniform sheet could not be obtained. Comparative example 3 (system in which a plasticizer is added to a highly polymerized vinyl chloride polymer) Vinyl chloride polymer polymerized at 40°C by a suspension method
100 parts by weight, 4 parts by weight of tin-based stabilizer, as a plasticizer
70 parts by weight of DOP was added and mixed in a super mixer. The resulting mixture was heated by a roll mill.
The mixture was kneaded at 160°C for 10 minutes and taken out in the form of a sheet.
After press molding, physical properties were measured according to Example 1. Table 1: Raw materials and polymerization conditions for the polypropylene-vinyl chloride graft copolymer used in the present invention
Furthermore, the physical property results of Examples and Comparative Examples are summarized in Table 2.

【table】

【table】

[Table] When compared at the same speed, the polypropylene-vinyl chloride graft copolymer polymerized by the suspension method (Comparative Example 1) has inferior tensile strength, and the blend system of vinyl chloride homopolymer and polypropylene (Comparative Example 2) has inferior tensile strength. ,
Due to poor compatibility, uniform sheets cannot be obtained and the quality is poor. Furthermore, the vinyl chloride homopolymer (Comparative Example 3) has a high melt viscosity and poor processability. Therefore, it is clear that the polypropylene-vinyl chloride graft copolymer composition of the present invention is useful as a vinyl chloride thermoplastic elastomer because it has excellent mechanical strength and impact resilience, and has a low melt viscosity.

Claims (1)

[Claims] 1 Manufactured by graft polymerization in the presence of polypropylene with a boiling n-heptane insoluble content of 30% or more and a melt flow index of 0.1 to 500 g/10 min in a state in which vinyl chloride monomer is substantially absent as a liquid phase. A vinyl chloride resin composition imparted with rubber-like elasticity, comprising 100 parts by weight of a polypropylene-vinyl chloride graft copolymer having a vinyl chloride content of 30 to 90% by weight and 30 to 200 parts by weight of a plasticizer.