JPS612715A - Rubber-reinforced resin with high impact resistance - Google Patents

Abstract

PURPOSE:To obtain the titled resin retaining both processability and rigidity, by graft polymerization, to an ethylene-alpha-olefin rubber, of an aromatic vinyl compound, vinyl cyanide or unsaturated carboxylic alkyl ester. CONSTITUTION:The objective resin can be obtained by graft polymerization, to (A) 10-60wt% of an ethylene-alpha-olefin rubber pref. with a molar ratio of the ethylene to alpha-olefin 5/1-1/3 (e.g. ethylene-propylene copolymer), of (B) 90- 10wt% of at least one sont of monomer selected from (1) aromatic vinyl compounds (e.g. styrene), (2) vinyl cyanides (e.g. acrylonitrile), and (3) unsaturated carboxylic alkyl esters [e.g., methyl (meth)acrylate], by appropriatly selecting types and amounts of said raw material rubber, initiator, molecular weight regulator, etc. This resin has a soluble <=40wt% in a THF/n-hexane (1/4 in vol. ratio) mixed solvent.

Description

[Detailed description of the invention] ■ Purpose of the invention [Industrial application field] The present invention relates to a rubber reinforced resin with excellent impact resistance.

[Conventional technology]

BACKGROUND ART Conventionally, as seen in high impact polystyrene (HIPS), ABS resins, etc., techniques have been used to introduce rubber into resins in order to improve the mechanical properties of resins, particularly impact resistance. In recent years, since non-conjugated diene rubber has better weather resistance than conjugated diene rubber such as borobukudene, impact-resistant and weather-resistant resins using non-conjugated diene rubber as the rubber component, such as ABS resin, have been developed. AC8 resin and AAS resin are attracting attention.

General VC improves impact resistance as the rubber content increases, but on the other hand, it causes a significant decrease in processability and rigidity, as well as poor appearance.

[Problem that the invention seeks to solve]

The problem solved by the present invention is the impact resistance of a rubber reinforced resin made of ethylene-α olefin rubber.

■ Structure of the Invention As a result of intensive research in view of the above-mentioned problems with rubber-reinforced resins, the present inventors have developed a rubber-reinforced graft polymer of rubber-reinforced resin in which the soluble content of a tetrahydrofuran-n-hexane mixed solvent is kept low. The present invention was based on the discovery that the resin has superior impact resistance compared to conventional rubber-reinforced resins.

That is, the present invention provides an ethylene-α olefin rubber containing f selected from the group consisting of an aromatic vinyl monomer, a vinyl cyanide monomer, and an unsaturated carboxylic acid alkyl ester.
Impact resistant, which is obtained by graft polymerization of one or more monomers, and in which the soluble content of the graft polymer in a mixed solvent of notetrahydrofuran and n-hexane (volume ratio 1:4) is 4ON or less. The present invention provides a rubber-reinforced resin with excellent properties and processability.

0 Ethylene-α olefin rubber The ethylene-α olefin rubber in the present invention is a binary copolymer consisting of ethylene and propylene or butene (
EPR), terpolymer (EPDM) consisting of ethylene, propylene or butene and non-conjugated diene, etc., and two or more types of fc are used.

Non-conjugated dienes in the terpolymer (EPDM) K include synchlopentadiene, ethylidene norbornene,
14-hexadiene, 14-cyclooctadiene, 15
-cyclooctadiene and the like.

Binary copolymers (EPR) and terpolymers (EPDM)
) The molar ratio of ethylene to propylene or butene in the VC is preferably in the range of 5:1 to 1=3.

Further, in the terpolymer (EPDM), it is preferable that the proportion of non-conjugated diene is in the range of 2 to 50 in terms of iodine value.

Examples of the aromatic vinyl monomer include styrene, α-methylstyrene, vinyltoluene, and methyl-α-methylstyrene.

Examples of vinyl cyanide monomers include acrylonitrile and methacrylate trile. Examples of unsaturated carboxylic acid alkyl esters include methyl acrylate,
Examples include ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxyethyl acrylate, as well as chrycidyl acrylate and chrysidyl methacrylate having an epoxy group in the molecule.

One or more monomers selected from the above-mentioned compounds constitute the K1M resin together with a monomeric ethylene-α-olefin rubber. Particularly preferred is one or more of styrene, acrylonitrile, and methyl methacrylate.

There is no particular restriction on the composition ratio of ethylene-α olefin rubber and monomer in the rubber reinforced resin, but from the physical properties of the resin, ethylene-α olefin rubber 5 to 95% by weight and monomer 95 to 5% by weight. It is preferable that the ethylene-α olefin rubber is 10 to 60% by weight, and the monomer is 90 to 60% by weight.
Preferably it is 40% by weight.

The soluble content of the kraft polymer of the rubber reinforced resin of the present invention in a tetrahydrofuran-〇-hexane mixed solvent (volume ratio 1:4) is 40% by weight or less.

If the soluble content exceeds 40% by weight, processability is improved, but impact resistance is significantly lowered, which is undesirable. In view of the balance between impact resistance and workability, it is advisable for the soluble content to be in the range of 10 to 4 ON, and especially I/rC is preferably in the range of 20 to 40 by weight.

The soluble content in the kraft polymer in the present invention means the t'L value measured under the following conditions.

The rubber reinforced resin was immersed in about 100 times the amount of MEK (methyl ethyl ketone) at room temperature for 24 hours, and then centrifuged (12,
OOORPM for 20 minutes) to separate MEK into soluble and insoluble components to obtain an insoluble component (graft polymer).

The obtained graft polymer was heat pressed (200°C).

5 minutes) Create a sheet with a thickness of about 1 day. One kraft polymer sheet was immersed in 200 m/200 m of tetrahydrofuran-n-hexane mixed solvent (volume ratio 1:4) for 48 hours at room temperature, passed through a 300-mesh mesh, and the soluble content was calculated from the gel content. .

Examples of polymerization methods for rubber-reinforced resins include conventionally known emulsion polymerization methods, suspension polymerization methods, bulk polymerization methods, and solution polymerization methods.

In addition, if the soluble content of the present invention is 40% by weight or less, such changes, changes in the type and amount of the initiator or molecular weight regulator, changes in the polymerization temperature, etc. may be made. Depending on the situation, we can add not only known additives such as dyes and pigments, antioxidants, plasticizers, antistatic agents, ultraviolet absorbers, lubricants, fillers, etc., but also acrylonitrile-styrene copolymers, styrene-maleic anhydride copolymers. Other thermoplastic resins such as , styrene-methyl methacrylate copolymer, polymethyl methacrylate, and polycarbonate can also be blended.

The present invention will be explained with reference to Examples, but the present invention is not limited to the Examples in any way.

EXAMPLE A kraft polymer was prepared using a known suspension polymerization method using 50 parts by weight of an ethylene-α olefin copolymer, 34 parts by weight of styrene, and 16 parts by weight of acrylonitrile.

In the polymerization, graft polymers with different soluble contents were obtained by using copolymers with different Mooney viscosities, changing the amount of initiator used, and changing the polymerization temperature.

Mata, 20 parts by weight of ethylene-α-olefin copolymer,
Graft polymerization was carried out using 60 parts by weight of styrene and 20 parts by weight of acrylonitrile based on a known solution polymerization method.

In addition, in the polymerization, kraft polymers with different soluble contents were obtained by using copolymers with different Mooney viscosities.

The graft polymerization recipe and polymerization results are shown in Table 1.

The obtained graft polymer was mixed with a separately produced styrene-acrylonitrile copolymer (70/30) to obtain a composition with a rubber content of 22% by weight. The impact strength and processability were evaluated.

The evaluation results are shown in Table-1.

1. Molding conditions 1. 8-precision resin injection molding machine FS-75 (3.5 oz.) Molding temperature: 240°C Mold temperature 2. 60°C 1. Effects of the invention Grafting of rubber reinforced resin using ethylene-α olefin rubber If the soluble content of the polymer in the tetrahydrofuran-n-hexane mixed solvent is 40% by weight or less, it has impact resistance of excellent 1f''.

Claims (1)

[Claims] 1. One or more monomers selected from the group consisting of aromatic vinyl monomers, vinyl cyanide monomers, and unsaturated carboxylic acid alkyl esters are graft-polymerized to ethylene-α-olefin rubber, and , grafted tetrahydrofuran-n-hexane mixed solvent (volume ratio 1:4)
A rubber-reinforced resin with excellent impact resistance, characterized by having a soluble content of 40% by weight or less.