JPH04264151A - Thermoplastic blend composition - Google Patents

Abstract

PURPOSE:To obtain the title composition having rubbery properties and excellent thermal weldability by blending a silane-grafted monoolefin copolymer rubber with a polyolefin plastic in a specified ratio. CONSTITUTION:This composition is prepared by blending 90-30 pts.wt. silane- grafted monoolefin copolymer (e.g. vinyl-trimethoxysilane-grafted ethylene/ propylene copolymer) with 10-79 pts.wt. polyolefin plastic (e.g. PP).

Description

[Detailed description of the invention]

0001

FIELD OF THE INVENTION This invention relates to thermoplastic blend compositions.

0002

2. Description of the Related Art Generally, rubber products do not exhibit thermoplasticity because they are three-dimensional chains created by chemical crosslinking such as vulcanization. On the other hand, thermoplastic elastomers exhibit thermoplasticity when processed at high temperatures, and at the same time exhibit rubber elasticity and high strength at room temperatures. Structurally, it has a two-phase structure consisting of hard segments that correspond to rubber crosslinking points and soft segments that have rubber-like properties. During high-temperature processing, the frozen hard segments thaw, exhibiting thermoplasticity as a whole, and when the temperature returns to room temperature, the hard segments freeze again and act as crosslinking points. Since thermoplastic elastomers (TPE) were first introduced to the world about 20 years ago, various types of thermoplastic elastomers have been developed. Among these, olefinic TPEs are widely used because they are inexpensive and have relatively well-balanced properties.

[0003] This olefin-based TPE is a polymer alloy containing ethylene-propylene-dienterpolymer (EPDM) as a rubber component and a polyolefin resin. Among them, ethylene propylene dienterpolymer (EPDM)
) and polypropylene (PP) have been developed.

0004

As mentioned above, general rubber products do not exhibit thermoplasticity, and therefore, when sheets made of these products are bonded together, thermal welding is impossible. Therefore, a method of bonding with adhesive is used. In this case, it is necessary to use a large amount of adhesive, and it takes a certain amount of time to bond.
Moreover, it was not always possible to maintain adhesiveness for a long period of time, which was a problem.

[0005] Also, commercially available olefin thermoplastic elastomers are made of blends of various polymers, so
Depending on the blend of polymers, it may lack elasticity and have poor rubber properties.

An object of the present invention is to solve the problems of the prior art described above and to provide a thermoplastic blend composition that has good thermal weldability and rubber-like properties.

[0007]

[Means for Solving the Problems] Based on the knowledge regarding thermoplastic elastomers, the present inventors have developed various methods to obtain a thermoplastic blend composition that has good thermal weldability and rubber-like properties. As a result of research and development, they focused on silane-grafted monoolefin copolymer rubber and determined the amount of mixture of this and polyolefin plastic.

That is, the thermoplastic blend composition of the present invention comprises silane-grafted monoolefin copolymer rubber 90
~30 parts by weight and 10 to 70 parts by weight of polyolefin plastic
It is made by blending parts by weight.

In the present invention, monoolefin copolymer rubbers include ethylene-propylene copolymer, ethylene-propylene-dienterpolymer, ethylene-butadiene copolymer, ethylene-butene-1 copolymer, and ethylene-butene-1 copolymer. 1. Amorphous random rubber-like copolymers mainly composed of olefins such as dienterpolymers are mentioned, and after silane grafting, silanol is produced in the presence of water by kneading with a catalyst (e.g. dibutyltin dilaurate). Can be crosslinked by condensation. Silane water crosslinking can also be carried out by applying the catalyst to the surface after forming it into a sheet etc. without adding a catalyst during kneading.
It can be used depending on the purpose.

Silane compounds include aliphatic compounds that contain hydrolyzable organic groups (for example, alkoxy groups such as methoxy, ethoxy, and butoxy groups) and that are reactive with free radical sites generated in organic polymers. Compounds having an unsaturated hydrocarbon group or hydrocarbonoxy group are suitable; typical examples include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, and radical generators used in the silane graft reaction. . This includes dicumyl peroxide (OCP),
Benzoyl peroxide (BPO), 2,5 dimethyl-2,5
-di(t-butyl-peroxy)hexyne-3 and other organic peroxides.

Examples of polyolefin plastics include isotactic polypropylene, copolymers of propylene and a small amount of other α-olefins (for example, propylene-ethylene copolymer, propylene-butene-1 copolymer, propylene-hexene-1 copolymer). Polymer, propylene/4-methylpentene-1 copolymer, high density polyethylene, medium density, low density polyethylene, linear low density polyethylene, ultra low density polyethylene, ethylene/vinyl acetate copolymer, ethylene/methyl acrylate copolymer polymer, ethylene/ethyl acrylate copolymer, ethylene/methyl methacrylate copolymer, ethylene/acrylic copolymer), and these may be used alone or in combination.

[0012] The mixing amount of the silane grafted monoolefin copolymer rubber and the polyolefin plastic must be 90 to 30 parts by weight and 10 to 70 parts by weight, respectively; if it is less than the specified value, the rubber properties will be poor, and the specified value will be exceeded. If it exceeds this, the heat weldability will be poor.

Therefore, by blending 90 to 30 parts by weight of a silane-grafted monoolefin copolymer rubber obtained by crosslinking monoolefin copolymer rubber by a silane water crosslinking method and 10 to 70 parts by weight of a polyolefin plastic, a good thermal It becomes possible to obtain a thermoplastic blend composition that has weldability and rubber-like properties.

In the present invention, antioxidants, lubricants, plasticizers, colorants, fillers, carbon black, etc. may be added as necessary in addition to the above-mentioned formulations.

[0015]

EXAMPLES Examples of the present invention will be described below with reference to comparative examples.

Among the ingredients shown in Table 1, except for the dibutyltin dilaurate masterbatch, various ingredients were added to a B-type Banbury mixer according to the formulations shown in the columns of Examples 1 to 5 and Comparative Examples 1 to 4 in Table 1. Knead until the temperature reaches 180°C for polypropylene and 140°C for high-density polyethylene. When each temperature was reached, the dibutyltin dilaurate masterbatch was put into a mixer, kneaded for 2 minutes, and then formed into a sheet using a 6-inch roll. 180 more
It was pressed for 10 minutes at ℃ and formed into a 1 mm thick sheet, which was used as a sample.

These samples were tested for tensile properties, adhesive strength and hardness, and the results are shown in the lower column of Table 1.

[0018] Each test for evaluation was conducted as follows. However, for the heat-fusion test samples, sheets with the same composition were melted using a Leister (a device that blows hot air like a dryer), and at the same time a small roll was pressed to adhere them.

Tensile properties: After being left in a constant temperature room at a temperature of 20°C for one day, it was punched out using a No. 3 dumbbell and subjected to a tensile test using a Schopper type tensile tester at a speed of 200 mm/min.
Tensile strength (TS) and elongation (TE) were measured.

Adhesive strength (thermal weldability): A sample with a width of 15 mm was tested using a Schopper type tensile tester as above, and was tested at 50 mm/
The film was evaluated as good (◯) when it broke in a T-shape at a speed of min. without peeling.

Hardness: Measured according to JIS K 6301.

[0022]

[Table 1]

As is clear from the results shown in Table 1,
Examples 1 to 5 using thermoplastic blend compositions of the present invention
The sample shows excellent values for all properties. On the other hand, Comparative Example 1 using silane grafted EP rubber alone,
The heat weldability was poor. In addition, Comparative Examples 2 and 3 in which the amount of silane grafted monoolefin copolymer and polyolefin plastic exceeded the specified value were those of Examples 1 to 3.
Compared to No. 5, the tensile strength and hardness values are larger, and the elongation is smaller. Furthermore, Comparative Example 4 using high-density polyethylene alone
The values of tensile strength, elongation, and hardness are larger than those of Examples 1 to 5. That is, the samples of Comparative Examples 2 to 4 are all plastic-like and rigid, that is, they lack elasticity.

Therefore, by blending a specified amount of silane-grafted monoolefin copolymer rubber and polyolefin plastic, a thermoplastic blend composition having rubber-like properties with excellent heat weldability and good tensile properties and hardness can be obtained. You will get something.

[0025]

In summary, according to the present invention, a thermoplastic blend composition having good heat weldability and rubber-like properties can be obtained, which is an excellent effect.

Claims (1)

[Claims] 1. A thermoplastic blend composition comprising a blend of 90 to 30 parts by weight of a silane-grafted monoolefin copolymer rubber and 10 to 70 parts by weight of a polyolefin plastic.