JPH11279290A - Recycled rubber molded product and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply produce the subject molded product suitable for reutilizing a vulcanized rubber, especially a weather strip of an automotive part and slightly deteriorating physical properties at a low cost by adding a thermoplastic resin to the vulcanized rubber. SOLUTION: This recycled rubber molded product is obtained by adding (B) a thermoplastic resin to (A) a cut or a pulverized material of a vulcanized rubber, melting the component A and press molding the resultant material. The amount of the added component B is 0.1-10 pts.wt. based on 100 pts.wt. of the component A. Furthermore, the component A is preferably a weather strip or a defective product rejected in a production process for the rubber or a waste rubber and is a shape memorizing vulcanized rubber having >=50% shaping ratio and >=50% shape recovery ratio and is prepared by vulcanizing a rubber composition containing an ethylene-α-olefin-nonconjugated polyene copolymer rubber comprising ethylene, a 3-20C α-olefin and a nonconjugated polyene and a polyolefin resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recycled rubber molded article for reusing vulcanized rubber and a method for producing the same, and more particularly to a recycled rubber molded article suitable for reusing a weather strip of an automobile part and a method for producing the same.

[0002]

2. Description of the Related Art Many rubber products are used for automobile parts. For example, styrene / butadiene copolymer rubber for tires and ethylene / propylene / non-conjugated diene copolymer rubber (EPDM) for weather strips. Vulcanized vulcanized rubber is used. Among such rubber products, the recycling of tires is progressing, but the recycling of other rubber products is hardly progressing, and effective recycling technology is required. However, since rubber is a crosslinked polymer that is crosslinked by vulcanization, it is difficult to mold it by simply heating without plasticizing, and it is difficult to recycle it into other molded articles.

Conventionally, a pan method has been known as a method for regenerating vulcanized rubber. The bread method is a method in which vulcanized rubber is finely pulverized and then desulfurized at high temperature and pressure to regenerate plasticity.
However, the conventional bread method is difficult to finely pulverize rubber,
Since high temperature and high pressure are required, the cost is increased, the physical properties of the rubber are greatly reduced, and the odor remains in the recycled rubber.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a recycled rubber molded article which can be easily manufactured at low cost by reusing vulcanized rubber, and in which the physical properties are small. Another object of the present invention is to reuse vulcanized rubber,
An object of the present invention is to propose a method for producing a recycled rubber molded article that can easily produce a low-cost recycled rubber molded article with a small decrease in physical properties.

[0005]

SUMMARY OF THE INVENTION The present invention relates to the following recycled rubber molded article and a production method. (1) A recycled rubber molded product obtained by adding a thermoplastic resin (A) to a cut or pulverized product of a vulcanized rubber [I] and press-molding the thermoplastic resin (A) in a molten state. (2) The recycled rubber molded article according to the above (1), wherein the addition amount of the thermoplastic resin (A) is 0.1 to 10 parts by weight based on 100 parts by weight of the vulcanized rubber [I]. (3) The recycled rubber molded article according to the above (1) or (2), wherein the vulcanized rubber [I] is a weather strip of an automobile part, a defective product or a waste rubber generated in a rubber manufacturing process. (4) The vulcanized rubber [I] according to any one of the above (1) to (3), wherein the vulcanized rubber [I] is a shape memory vulcanized rubber having a shape shaping ratio of 50% or more and a shape recovery ratio of 50% or more. 2. A recycled rubber molded article according to item 1. (5) The vulcanized rubber [I] is composed of ethylene and 3 to 2 carbon atoms.
Vulcanization obtained by vulcanizing a rubber composition [II] containing an ethylene / α-olefin / non-conjugated polyene copolymer rubber (B) comprising a α-olefin of 0 and a non-conjugated polyene and a polyolefin resin (C) The recycled rubber molded article according to any one of the above (1) to (4), which is a rubber. (6) The rubber composition [II] is a composition in which particles of a polyolefin resin (C) are micro-dispersed in an ethylene / α-olefin / non-conjugated polyene copolymer rubber (B), The recycled rubber molded article according to the above (5), wherein the average dispersed particle diameter of (C) is 0.1 to 100 µm. (7) The rubber composition [II] contains 5 to 50 parts by weight of the polyolefin resin (C) based on 100 parts by weight of the ethylene / α-olefin / non-conjugated polyene copolymer rubber (B). Or the recycled rubber molded article according to (6). (8) Polyolefin resin (C) has a melting point of 70 to 20
The recycled rubber molded article according to any one of the above (5) to (7), which is at 0 ° C. (9) After cutting or pulverizing the vulcanized rubber [I], the thermoplastic resin (A) is added, the thermoplastic resin (A) is melted and press-molded, and any of the above (1) to (8) A method for producing a recycled rubber molded article for producing the recycled rubber molded article according to the above item. (10) After cutting or pulverizing the vulcanized rubber [I], it is heated to the melting point of the polyolefin resin (C) or higher, and then the thermoplastic resin (A) is added to melt the thermoplastic resin (A). A method for producing a recycled rubber molded article, comprising press-molding and producing the recycled rubber molded article according to any one of the above (5) to (8). (11) Thermoplastic resin (A) in the mold for press molding
(9) or (10), wherein the thermoplastic resin (A) is melted by heating to a temperature not lower than the melting point of the thermoplastic resin (A). (12) After heating to a temperature equal to or higher than the melting point of the polyolefin resin (C), the thermoplastic resin (A) is added by adding the thermoplastic resin (A) while maintaining a temperature at which the thermoplastic resin (A) can be melted. Is melted and is not heated in a mold for press molding.

The thermoplastic resin (A) used in the present invention is not particularly limited as long as it is a thermoplastic resin, and examples thereof include polyethylene, polypropylene, polybutene-1, and poly-4-methylpentene-1. Among these, polypropylene is preferred. The polypropylene may be a homopolymer of propylene or a small amount of other monomers such as 2 or 4-20 carbon atoms, preferably 2 or 4-
It may be a copolymer with 10 α-olefins. The thermoplastic resin (A) can be used alone or in combination of two or more.

The thermoplastic resin (A) is preferably used in the form of a powder so that it can easily adhere to the surface of the vulcanized rubber [I] uniformly. The amount of the thermoplastic resin (A) used is preferably 0.1 to 10 parts by weight, more preferably 1 to 5 parts by weight, per 100 parts by weight of the vulcanized rubber [I].

The recycled rubber molded article of the present invention is a rubber molded article mainly made of vulcanized rubber [I]. The thermoplastic resin (A) is cut or pulverized from the vulcanized rubber [I]. It is a rubber molded product obtained by press-molding the thermoplastic resin (A) in a molten state.

As the vulcanized rubber [I], it is preferable to reuse the rubber used as a rubber product, and it may be a foam (sponge) or a non-foam (solid vulcanized rubber). . Specific examples of the vulcanized rubber [I] to be reused include a weather strip of an automobile part, a defective product generated in a rubber manufacturing process, a waste rubber contained in city rubber, industrial waste, and the like. . Vulcanized rubber obtained by vulcanizing a rubber composition in which a polyolefin resin is dispersed in ethylene-propylene-non-conjugated diene copolymer (EPDM) or EPDM is widely used for weather strips of automobile parts. Can preferably use such a vulcanized rubber of EPDM as a vulcanized rubber [I] as a raw material.

[0010] The vulcanized rubber [I] has a shape-forming ratio of 5
It is preferable to use a shape-memory vulcanizate having a shape recovery rate of 0% or more, preferably 80 to 100%, and a shape recovery rate of 50% or more, preferably 60 to 100%. The shape shaping rate and the shape recovery rate are values obtained by the following method.

<< Shape-Shaping Rate of Foam >> 1) A vulcanized tube sponge having a height of 18 mm shown in FIG. 1 was cut into a length of 50 mm and then compressed by 50% with a jig for a compression set test. Crushed and put in an oven at 180 ° C. for 5 minutes. 2) Then, water-cool for 5 minutes while being crushed. 3) After removing the sample from the jig and leaving it at room temperature (25 ° C.) for one day, the height h1 (mm) is measured and calculated from the following equation (1). Shape shaping ratio (%) = (18−hl) / 18 × 100 (1)

<< Recovery Rate of Foam Shape >> A vulcanized tubular sponge having a height of 18 mm shown in FIG.
, And then taken out, left at room temperature (25 ° C.) for one day, and measured for height h2 (mm). Shape recovery rate (%) = h2 / 18 × 100 (2)

<< Shape shaping ratio of non-foamed body >> 1) From a vulcanized sheet having a thickness of 2 mm, a width of 10 mm and a length of 80
mm test piece was punched out, and a distance of 3 mm
Draw two marking lines at 0 mm. 2) This test piece is stretched to a distance of 60 mm between the marked lines using a jig, and then placed in an oven at 180 ° C. for 5 minutes. 3) Then, water-cooling is performed for 2 minutes while the extension is given. 4) Remove the test piece from the jig to release the extension,
(5 ° C.) for one day, and then the distance (a) between the marked lines is measured and calculated from the following equation (3). Shape shaping ratio (%) = (a-30) / (60-30) × 100 (3)

<< Shape recovery rate of non-foamed body >> 1) From a vulcanized sheet having a thickness of 2 mm, a width of 10 mm and a length of 80
mm test piece was punched out, and a distance of 3 mm
Draw two marking lines at 0 mm. 2) The test piece was left in an oven at 180 ° C. for 5 minutes, then taken out, left at room temperature for 30 minutes, the distance (b) between the marked lines was measured, and calculated from the following equation (4). Note that a in the formula is the distance between the marked lines obtained at the time of measuring the shape shaping ratio. Shape recovery rate (%) = (ab) / (a−30) × 100 (4)

As the vulcanized rubber [I], an ethylene / α-olefin / non-conjugated polyene copolymer rubber (B) comprising ethylene, an α-olefin having 3 to 20 carbon atoms, and a non-conjugated polyene; A vulcanized rubber obtained by vulcanizing a rubber composition [II] containing the resin (C) is preferable. In particular, a rubber composition [II] in which particles of a polyolefin resin (C) are micro-dispersed in an ethylene / α-olefin / non-conjugated polyene copolymer rubber (B), wherein the average dispersion of the polyolefin resin (C) is Particle size 0.1-100μ
m, preferably 0.2 to 10 μm [I
Vulcanized rubber obtained by vulcanizing I] is preferred. Specific examples of such vulcanized rubber [I] include weather strips for automobile parts.

Here, the average particle diameter of the dispersion is as follows: vulcanized rubber [I]
Alternatively, it is a value obtained from a 10000 magnification photograph of a section of the rubber composition [II] taken with an electron microscope. The value obtained from the section of the vulcanized rubber [I] and the rubber composition [II]
Are almost the same.

The ethylene / α-olefin / non-conjugated polyene copolymer rubber (B) is composed of ethylene and C3-C3.
An ethylene / α-olefin / non-conjugated polyene copolymer rubber obtained by random copolymerization of α-olefin of No. 20 and a non-conjugated polyene.

The α-olefin is an α-olefin having 3 to 20 carbon atoms.
-Olefins, among them propylene, 1-butene,
Α-olefins having 3 to 10 carbon atoms such as 4-methyl-1-pentene, 1-hexene and 1-octene are preferred, and propylene and 1-butene are particularly preferred. That is, as the ethylene / α-olefin / non-conjugated polyene copolymer rubber (B), an ethylene / propylene / non-conjugated polyene copolymer rubber or an ethylene / 1-butene / non-conjugated polyene copolymer rubber is preferable.

The ethylene / α-olefin / non-conjugated polyene copolymer rubber (B) has a molar ratio of ethylene / α-olefin (ethylene / α-olefin) of 60/40 to 60/40.
Those in the range of 85/15, preferably 65/35 to 80/20 are desirable.

As the non-conjugated polyene, a cyclic or chain non-conjugated polyene is used. Examples of the cyclic non-conjugated polyene include 5-ethylidene-2-norbornene, dicyclopentadiene, 5-vinyl-2-norbornene, norbornadiene, and methyltetrahydroindene. Examples of the chain non-conjugated polyene include 1,4-hexadiene, 7-methyl-1,
6-octadiene, 8-methyl-4-ethylidene-1,
Examples thereof include 7-nonadiene and 4-ethylidene-1,7-undecadiene. These non-conjugated polyenes are used alone or in combination of two or more, and the copolymerization amount thereof is
It is desirable that the iodine value is 1 to 40, preferably 2 to 35, more preferably 3 to 30.

The intrinsic viscosity [η] of the ethylene / α-olefin / non-conjugated polyene copolymer rubber (B) measured in decahydronaphthalene at 135 ° C. is 0.8 to 4 dl / g, preferably 1 to 3.5 dl. / G, more preferably 1.1 to
It is desirable to be in the range of 3 dl / g. Ethylene α-
The olefin / non-conjugated polyene copolymer rubber (B) may be a modified product obtained by graft copolymerization of an unsaturated carboxylic acid or a derivative thereof, for example, an acid anhydride. Ethylene / α-olefin / non-conjugated polyene copolymer rubber (B)
The most preferred is an ethylene / propylene / non-conjugated diene copolymer rubber.

The ethylene / α-olefin / non-conjugated polyene copolymer rubber (B) may be used alone or in a combination of two or more.
Ethylene and α-olefin having the above properties
The non-conjugated polyene copolymer rubber (B) is described in “Polymer Production Process (published by Industrial Research Institute, Inc., pp. 309-33).
0) "and the like.

The polyolefin resin (C) may be a crystalline resin or an amorphous resin.
Crystalline resins are preferred. Examples of the crystalline resin used as the polyolefin resin (C) include α having 2 to 12 carbon atoms.
-Olefin homopolymers or copolymers.

This polymerization type may be any of random polymerization and block polymerization. In the case of a random copolymer, an α-olefin copolymer containing the smaller α-olefin structural unit in an amount of usually 40 mol% or less, preferably 30 mol% or less is desirable. Examples of the α-olefin having 2 to 12 carbon atoms include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene and 1-decene.

As the crystalline polyolefin resin (C), polypropylene and polybutene are preferred. Specifically, a propylene homopolymer, a copolymer of propylene and one or more α-olefins having 2 to 12 carbon atoms, a 1-butene homopolymer, and a 1-butene and one or more carbon atoms of 2 Copolymers with α-olefins of from 1 to 12 are preferred. In the case of a copolymer, the content of the α-olefin copolymerized with propylene or 1-butene is desirably 20 to 1 mol%, preferably 15 to 1 mol%.

Examples of the amorphous resin used as the polyolefin resin (C) include an ethylene / cyclic olefin copolymer.

The polyolefin resin (C) has a melting point (Tm) of 70 to 200 measured by a differential scanning calorimeter (DSC).
C, preferably 80 to 180C. The aspect ratio (major axis / minor axis) of the dispersed particles of the polyolefin resin (C) is preferably 5 or less, more preferably 1 to 3. When the aspect ratio is 5 or less, the microdispersion of the polyolefin resin (C) particles is good. The polyolefin resin (C) can be used alone or in combination of two or more.

The polyolefin resin (C) is ethylene α
-It is preferable that the polyolefin resin (C) is microdispersed in the olefin / non-conjugated polyene copolymer rubber (B), but the morphology (phase form) of the polyolefin resin (C) is different from that of the molten polyolefin resin (C). This can be achieved by applying a shearing force. For example, when the polyolefin resin (C) is a propylene homopolymer (C),
In the twin-screw extruder, a specific energy of 0.01 kW · hr / kg or more, preferably 0.02 kW · hr / kg or more may be given to the propylene homopolymer (C) under the temperature conditions described above. When the average dispersed particle diameter of the polyolefin resin (C) exceeds 100 μm due to insufficient temperature conditions and insufficient shear energy, the physical properties of the recycled rubber molded article tend to decrease.

On the other hand, the polyolefin resin (C) has too high an affinity for the ethylene / α-olefin / non-conjugated polyene copolymer rubber (B), for example, an ethylene / α-olefin / non-conjugated polyene copolymer When the rubber (B) and the polyolefin resin (C) are compatible with each other at a molecular level, there is a tendency that the rubber elasticity is reduced. Therefore, it is preferable that the types of the polyolefin resin (C) and the ethylene / α-olefin / non-conjugated polyene copolymer rubber (B) are selected in a range in which both are not compatible at the molecular level.

The content ratio of each component of the rubber composition [II] is as follows:
3 to 50 parts by weight, preferably 5 to 40 parts by weight, more preferably 5 to 30 parts by weight of polyolefin resin (C) based on 100 parts by weight of ethylene / α-olefin / non-conjugated polyene copolymer rubber (B) It is desirable to have.

The compounding amount of the polyolefin resin (C) satisfies the above range, and the hardness of the rubber composition [II] (JIS
A hardness (A) defined by K6301) and the blending amount (X) of the polyolefin resin (C) are as follows: Y = (0.5 ± 0.2) X + a [where X is the polyolefin resin (C) (Unit: parts by weight, the total amount of components (B) and (C) is 100 parts by weight), and a is obtained by subtracting the increase in hardness due to the blending of the polyolefin resin (C) from the hardness of the rubber composition. Hardness. ] Is preferably satisfied.

The blending amount of the polyolefin resin (C) satisfies the above range, and the hardness (JIS K) of a non-foamed vulcanized rubber molded product obtained by vulcanizing the rubber composition [II].
A = Y) and the blending amount (X) of the polyolefin resin (C) defined by the formula 6301 are as follows: Y = (0.5 ± 0.2) X + a [where X is the polyolefin resin (C). The compounding amount (unit: parts by weight, the total amount of components (B) and (C) was 100 parts by weight), and a was obtained by subtracting the increase in hardness due to the compounding of the polyolefin resin (C) from the hardness of the rubber molded article. Hardness. ] Is preferably satisfied.

In the rubber composition [II], the above-mentioned ethylene • α-
In addition to the olefin / non-conjugated polyene copolymer rubber (B) and the polyolefin resin (C), at least a vulcanizing agent is used, and if necessary, other components such as a vulcanization accelerator, a vulcanization aid, and other components. Rubber, softener, reinforcing material, filler,
Compounding agents that are commonly used in the production of rubber, such as processing aids, pigments, antioxidants, and foaming agents, may be added.

Examples of the vulcanizing agent include a sulfur compound and an organic peroxide. Examples of the sulfur compound include sulfur, sulfur chloride, sulfur dichloride, morpholine disulfide, alkylphenol disulfide, tetramethylthiuram disulfide, selenium dithiocarbamate and the like. Of these, sulfur is preferred. The amount of the sulfur compound to be used is generally 0.1 to 10 parts by weight, preferably 0.3 to 5 parts by weight, based on 100 parts by weight of the ethylene / α-olefin / non-conjugated polyene copolymer rubber (B). More preferably, 0.
It is desirable to use 5 to 3 parts by weight.

Examples of the organic peroxide include dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, 2,5-dimethyl-
2,5-di (t-butylperoxy) hexyne-3, di-t-butyl peroxide, di-t-butylperoxy-3,3,5-trimethylcyclohexane, t-dibutyl hydroperoxide and the like. Among them, dicumyl peroxide, di-t-butyl peroxide and di-t-butylperoxy-3,3,5-trimethylcyclohexane are preferred. The amount of the organic peroxide to be used is usually 3 × 10 ^{−3 to} 5 × with respect to 100 g of the ethylene / α-olefin / non-conjugated polyene copolymer rubber (B).
It is desirably 10 ⁻² mol, preferably 1 × 10 ^{−3 to} 3 × 10 ⁻² mol.

When a sulfur compound is used as a vulcanizing agent, it is preferable to use a vulcanization accelerator in combination. Examples of the vulcanization accelerator include N-cyclohexyl-2-benzothiazolesulfenamide, N-oxydiethylene-2-
Benzothiazolesulfenamide, N, N'-diisopropyl-2-benzothiazolesulfenamide, 2
-Mercaptobenzothiazole, 2- (2,4-dinitrophenyl) mercaptobenzothiazole, 2- (2,2
6-diethyl-4-morpholinothio) thiazole compounds such as benzothiazole and dibenzothiazyl-disulfide; guanidine compounds such as diphenylguanidine, triphenylguanidine and diorthotolylguanidine; acetaldehyde-aniline condensate, butyraldehyde- Aldehyde amine compounds such as aniline condensates;
Imidazoline compounds such as 2-mercaptoimidazoline; thiourea compounds such as diethylthiourea and dibutylthiourea; thiuram compounds such as tetramethylthiuram monosulfide and tetramethylthiuram disulfide; zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate and diethyldithiocarbamate Dithionate compounds such as tellurium; xanthate compounds such as zinc dibutylxanthogenate; and zinc white. These vulcanization accelerators are used in an amount of 0.1 to 20 parts by weight, preferably 0.2 to 10 parts by weight, based on 100 parts by weight of the ethylene / α-olefin / non-conjugated polyene copolymer rubber (B). , More preferably 0.5 to 5
It is desirably in parts by weight.

When an organic peroxide is used as a vulcanizing agent, it is preferable to use a vulcanizing aid in combination. Examples of the vulcanization aid include sulfur; quinone dioximes such as p-quinone dioxime; (meth) acrylic compounds such as ethylene glycol dimethacrylate and trimethylolpropane trimethacrylate; diallyl phthalate, triallyl isocyanurate and the like. Allyl compound; other maleimide compounds, divinylbenzene (DVB), and the like.

The amount of the vulcanization aid used is preferably 0.5 to 2 moles, and more preferably equal to 1 mole of the organic peroxide used. Other rubbers include natural rubber, styrene / butadiene rubber, nitrile rubber, chloroprene rubber, acrylic rubber, hydrogenated NBR, and the like.

As the softening agent, a softening agent usually used for rubber can be used. For example, petroleum softening agents such as process oil, lubricating oil, paraffin, liquid paraffin, petroleum asphalt, petrolatum; coal tar softening agents such as coal tar and coal tar pitch; castor oil, rapeseed oil, soybean oil, coconut oil, etc. Fatty oil-based softeners; tall oil; waxes such as beeswax, carnauba wax and lanolin; fatty acids such as ricinoleic acid, palmitic acid, stearic acid, barium stearate and calcium stearate or metal salts thereof; naphthenic acid or metal soaps thereof Pine oil, rosin or derivatives thereof; synthetic polymer substances such as terpene resin, petroleum resin, coumarone indene resin, atactic polypropylene; ester plasticizers such as dioctyl phthalate, dioctyl adipate, dioctyl sebacate; diisododecyl carbonate Etc. System plasticizers; Other microcrystalline wax, sub (factice), liquid polybutadiene, modified liquid polybutadiene, liquid Thiokol, and hydrocarbon synthetic lubricating oil. The amount of the softening agent is preferably 200 parts by weight or less based on 100 parts by weight of the ethylene / α-olefin / non-conjugated polyene copolymer rubber (B).

As the reinforcing material, for example, SRF, GP
Various carbon blacks such as F, FEF, MAF, ISAF, SAF, FT, and MT, and finely divided silicic acid. As the filler, for example, light calcium carbonate,
Heavy calcium carbonate, talc, clay and the like. The amounts of these reinforcing materials and fillers are based on the ethylene / α-olefin / non-conjugated polyene copolymer rubber (B).
The amount is usually 200 parts by weight or less, preferably 150 parts by weight or less based on 100 parts by weight.

As processing aids, processing aids used in ordinary rubber processing can be used. Examples of such processing aids include higher fatty acids such as ricinoleic acid, stearic acid, palmitic acid, and lauric acid; higher fatty acid salts such as barium stearate, calcium stearate, and zinc stearate; ricinoleic acid esters, stearic acid esters; And higher fatty acid esters such as palmitic acid esters and lauric acid esters.
The amount of these processing aids is usually about 10 parts by weight or less, preferably about 1 to 5 parts by weight, based on 100 parts by weight of the ethylene / α-olefin / non-conjugated polyene copolymer rubber (B). It is desirable.

Examples of the pigment include known inorganic pigments (for example, titanium white) and organic pigments (for example, naphthol green B). The compounding amount of these pigments is
The amount is preferably at most 20 parts by weight, and more preferably at most 10 parts by weight, based on 100 parts by weight of the ethylene / α-olefin / non-conjugated polyene copolymer rubber (B).

Examples of the anti-aging agent include aromatic secondary amine-based stabilizers such as phenylbutylamine and N, N'-di-2-naphthyl-p-phenylenediamine; dibutylhydroxytoluene, tetrakis [methylene (3,5 −
Phenolic stabilizers such as di-t-butyl-4-hydroxy) hydrocinnamate] methane; bis [2-methyl-4- (3-n-alkylthiopropionyloxy)-
Thioether stabilizers such as [5-t-butylphenyl] sulfide; dithiocarbamate stabilizers such as nickel dibutyldithiocarbamate; The amount of such an antioxidant is usually 0.1 to 5 parts by weight, preferably 0.5 to 3 parts by weight, per 100 parts by weight of the ethylene / α-olefin / non-conjugated polyene copolymer rubber (B). It is desirably in parts by weight.

The vulcanized rubber [I] obtained by vulcanizing the rubber composition [II] may be non-foamed or foamed. As the foaming agent used for forming the foam, any of commercially available foaming agents can be suitably used. For example, sodium bicarbonate, sodium carbonate,
Inorganic blowing agents such as ammonium bicarbonate, ammonium carbonate and ammonium nitrite; nitroso compounds such as N, N'-dinitroterephthalamide and N, N'-dinitrosopentamethylenetetramine; azodicarbonamide, azobisisobutyronitrile Azo compounds such as azocyclohexylnitrile, azodiaminobenzene, barium azodicarboxylate; benzenesulfonyl hydrazide, toluenesulfonyl hydrazide, p, p'-oxybis (benzenesulfonyl hydrazide) diphenyl sulfone-3,3'-disulfenyl hydrazide Sulfonyl hydrazide compounds such as calcium azide;
Azide compounds such as 4,4'-diphenylsulfonyl azide and paratoluenesulfonyl azide;
Among them, azo compounds, sulfonyl hydrazide compounds and azide compounds are preferably used.

The mixing amount of these foaming agents is appropriately selected so that the specific gravity of the foam after vulcanization and foaming becomes 0.01 to 0.9, but the ethylene / α-olefin / non-conjugated polyene copolymer is used. Usually 0.5 to 100 parts by weight of rubber (B)
30 parts by weight, preferably 1 to 20 parts by weight, more preferably 2 to 10 parts by weight.

If necessary, a foaming aid may be used together with a foaming agent. The addition of a foaming aid is effective in controlling the decomposition temperature of the foaming agent, making the air bubbles uniform, and the like. Examples of the foaming aid include organic acids such as salicylic acid, phthalic acid, stearic acid and oxalic acid, urea and derivatives thereof.

The rubber composition [II] can be produced by micro-dispersing particles of the polyolefin resin (C) in the ethylene / α-olefin / non-conjugated polyene copolymer rubber (B). In order to micro-disperse the particles of the polyolefin resin (C), 1) the ethylene / α-olefin / non-conjugated polyene copolymer rubber (B) and the polyolefin resin (C) are mixed and kneaded in a molten state to obtain a polyolefin resin. (C) a method of imparting a shearing action (shearing force) to the rubber mixture comprising an ethylene / α-olefin / non-conjugated polyene copolymer rubber (B) and an organic solvent; A method of kneading the rubber mixture and the polyolefin resin (C) and removing the solvent is used. In any method, when adding other additives, the polyolefin resin (C) is uniformly dispersed by the above method, and then the other additives are added to the dispersion (kneaded material) and kneaded. Is preferred.

As the method 1), the following method is specifically exemplified. That is, the ethylene / α-olefin / non-conjugated polyene copolymer rubber (B) and the polyolefin resin (C) are 200 to 300 in a twin-screw extruder.
Mix and knead at 2 ° C for 2 to 10 minutes. Next, the obtained kneaded material and other additives are kneaded at 80 to 170 ° C. for 3 to 10 minutes using a mixer such as a Banbury mixer. Next, a vulcanizing agent, a vulcanization aid, and the like are additionally mixed with the obtained kneaded material using rolls such as an open roll, and kneaded at a roll temperature of 40 to 80 ° C. for 3 to 30 minutes to dispense. A ribbon-shaped or sheet-shaped rubber composition [II] (unvulcanized rubber compound) is prepared.

As the method 2), the following method is specifically exemplified. That is, a rubber mixture comprising 100 parts by weight of an ethylene / α-olefin / non-conjugated polyene copolymer rubber (B) and 3 to 10 parts by weight of an organic solvent is introduced into the extruder from a supply section of a multi-stage vented extruder. Then, the polyolefin resin (C) is introduced into the extruder from another supply section under an inert gas atmosphere, and the rubber mixture and the polyolefin resin (C) are kneaded and the solvent is removed.
Thereafter, other additives are kneaded by the same method as exemplified in the above 1), and then a vulcanizing agent, a vulcanization aid and the like are kneaded to prepare a rubber composition [II].

For the vulcanization, the following method is exemplified. That is, the rubber composition [II] is molded into an intended shape by an extruder, a calender roll, a press, an injection molding machine, a transfer molding machine, and the like, and simultaneously with molding or in a vulcanizing tank, the molded product is usually 150 ~ 1 to 270 ° C
Vulcanization by heating for 0 minutes, or foaming and vulcanization. As the vulcanizing tank, steam vulcanizing cans,
Examples include a hot air vulcanizing tank, a fluidized bed of glass beads, a molten salt vulcanizing tank, and a microwave tank. These vulcanizing tanks are used alone or in combination.

In the production method of the present invention, after the vulcanized rubber [I] is cut or pulverized, the thermoplastic resin (A) is added, and the thermoplastic resin (A) is melted and press-molded. Manufacture recycled molded products. When the vulcanized rubber [I] is a vulcanized product of the rubber composition [II],
Before adding the thermoplastic resin (A), it is preferable to heat the polyolefin resin (C) to the melting point or higher.

The vulcanized rubber [I] is preferably cut or pulverized so as to have an average particle size of 10 mm or less, preferably 5 to 0.1 mm. In order to cut or pulverize the vulcanized rubber [I], a known cutting device or pulverizing device such as a rotary cutter, a rotating disk type pulverizing device, a cutting type pulverizing device, a gas flow pulverizing type pulverizing device, and a freeze pulverizing device may be used. it can.

The thermoplastic resin (A) is in the form of a powder, preferably having an average particle diameter of 500 to 20 μm, in order to uniformly adhere to the surface of the cut or ground product of the vulcanized rubber [I].
m, more preferably 200 to 50 μm. The addition amount of the thermoplastic resin (A) is 0.1 to 10 parts by weight, preferably 1 to 5 parts by weight, per 100 parts by weight of the vulcanized rubber [I]. If the added amount of the thermoplastic resin (A) is small, molding becomes difficult, while if it is large, the recycled molded product becomes hard, which is not preferable as a recycled rubber product.

The added thermoplastic resin (A) can be melted by heating in a mold of a press molding machine to a temperature equal to or higher than the melting point of the thermoplastic resin (A). When heating to a temperature equal to or higher than the melting point of the polyolefin resin (C) before adding the thermoplastic resin (A), a temperature at which the thermoplastic resin (A) can be melted after heating the vulcanized rubber [I]. It is also possible to employ a method in which the thermoplastic resin (A) is added to melt the thermoplastic resin (A) in a state where the temperature is maintained, and the mixture is not heated in the mold of the press molding machine but press-molded in a cooling mold. it can. The temperature at which the thermoplastic resin (A) is melted is preferably equal to or higher than the melting point of the polyolefin resin (C).

In the production method of the present invention, the thermoplastic resin (A) is added to the cut or pulverized product of the vulcanized rubber [I], and the molded product is melted. Thus, it is possible to easily obtain a recycled rubber molded product having a small decrease in physical properties. The recycled rubber molded article of the present invention thus produced can be used as a sheet, a cushion material, a sealing material, a roll, a hose, and the like.

[0056]

The recycled rubber molded article of the present invention is a molded article obtained by adding a thermoplastic resin to a cut or pulverized product of vulcanized rubber and press-molding the resin in a molten state. By reusing rubber, it can be easily manufactured at low cost, and the decrease in physical properties is small. In the method for producing a recycled rubber molded article of the present invention, after the vulcanized rubber is cut or pulverized, a thermoplastic resin is added, and the thermoplastic resin is melted and press-molded. By utilizing such a method, it is possible to easily manufacture a recycled rubber molded article having a small decrease in physical properties at low cost.

[0057]

Next, an embodiment of the present invention will be described.

Example 1 First, the ingredients shown in Table 1 were mixed with a twin-screw extruder (Toshiba Machine Co., Ltd.)
The mixture was kneaded and kneaded in a molten state with a set temperature of 230 ° C. and a screw rotation speed of 200 rpm by a 50φ twin screw extruder, L / D = 45) to obtain a compound-A. The specific energy during mixing and kneading was 0.06 kWh / kg.

[0059]

[Table 1] * 1 Ethylene / propylene / 5-ethylidene-2-norbornene copolymer rubber, ethylene / propylene molar ratio = 72/63, intrinsic viscosity [η] measured in 135 ° C. decahydronaphthalene = 2.7 dl / g, Iodine value = 2
2 * 2 Vicat softening point = 150 ° C

A section of the above Formulation-A was stained with ruthenic acid, and the section was scanned with a scanning electron microscope (manufactured by JEOL Ltd .: T330).
A, trademark), a 10,000-fold photograph was taken, and the average dispersed particle size of the crystalline polypropylene particles in the photograph was determined using an image analyzer (LA-500, manufactured by Pierce Co., Ltd.). It was 3 μm.

Next, using the above-mentioned compounding agent-A in the ratio shown in Table 2, kneading was carried out with a BB2 type Banbury mixer (manufactured by Kobe Steel) to prepare a rubber composition-A. It was wound around an open roll (manufactured by Nippon Roll Co., Ltd.) to obtain a rubber composition-B having a shape memory having the composition shown in Table 3. A ribbon was cut from the roll.

[0062]

[Table 2] * 1 Compounds shown in Table 1 * 2 Sakai Chemical Co., Ltd. * 3 Asahi Carbon Co., Ltd., Asahi # 50, trademark * 4 Idemitsu Kosan Co., Ltd., Diana Process Oil PW
380, trademark

[0063]

[Table 3] * 1 Rubber composition shown in Table 2 * 2 Neoservon N1000S manufactured by Eiwa Chemical Co., Ltd.
W, trademark * 3 Sanshin Chemical Co., Ltd., Suncellar M, trademark * 4 Sanshin Chemical Co., Ltd., Suncellar BZ, trademark * 5 Sanshin Chemical Co., Ltd., Suncellar 22, trademark * 6 Sanshin Chemical Co., Ltd., Suncellar TET, trademark

Next, the obtained ribbon-shaped rubber composition-B
Was extruded with a 60 mm diameter extruder in which the temperature of the die and the barrel was controlled at 60 ° C. and the screw temperature was controlled at 40 ° C., and the obtained molded product was continuously led to a hot air tank controlled at 220 ° C. The mixture was heated for 5 minutes to be vulcanized and foamed to obtain a tubular sponge having the shape shown in FIG. FIG. 2 shows a cross section of a base used for obtaining the sponge. Table 4 shows the sponge physical properties.

[0065]

[Table 4]

Notes in Table 4 * 1 Measurement of Specific Gravity: A 20 mm long tube-shaped test piece was punched out from the vulcanized tube-shaped sponge of FIG. 1, and dirt on the surface was wiped off with alcohol. This test piece is kept at 25
Automatic hydrometer under atmosphere (Toyo Seiki Seisakusho M-1 type)
And the specific gravity was measured from the difference between the masses in air and pure water.

* 2 Water absorption measurement: A 20 mm long tube-shaped test piece was punched out from the vulcanized tube-shaped sponge of FIG. 1 and the weight of the test piece was measured. Water was poured at least 100 mm from the bottom into the desiccator with the following suction port, and the test piece was placed therein. The test piece was submerged under the water by a wire mesh so as not to float. In this state, the inside of the desiccator was evacuated with a vacuum pump and kept at 635 mmHg. After 3 minutes, the reduced pressure was released, and the system was held for another 3 minutes. After taking out the test piece and wiping off water droplets on the surface, the weight was measured, and the water absorption was calculated from the following equation. Water absorption (%) = (W2-W1) / W1 × 100 (where W1: weight before immersion (g), W2: weight after immersion (g))

* 3 Tensile test: JIS K 6301 (1989) was obtained from the vulcanized tubular sponge of FIG.
The test piece was punched out using a No. 3 type dumbbell described in (1). According to the method defined in the JIS K6301 third term by using this test specimen, measurement temperature 25 ° C., subjected to tensile test at a tensile rate of 500 mm / min condition, tensile stress at break T _B and tensile elongation at break E _B was measured.

* 4 Compression set test: The vulcanized tubular sponge of FIG. 1 was cut into a length of 30 mm and attached to a compression set measuring die. Compress the test piece so that the height becomes 1/2 of the previous height by applying a load.
And heat-treated for 200 hours. 3
After leaving to cool for 0 minutes, the height of the test piece was measured, and the compression set was calculated from the following equation. Compression set (%) = (t0−t1) / (t0−t2) ×
100 (where, t0: height of the test piece before the test, t1: height after the test piece is heat-treated and allowed to cool for 30 minutes, t2: height of the test piece attached to the measuring die )

* 5 Shape shaping ratio: 1) After cutting a vulcanized tube-shaped sponge having a height of 18 mm in FIG. 1 to a length of 5 mm, it was compressed by 50% with a jig for a compression set test and crushed. In that state, it was left in an oven at 180 ° C. for 5 minutes. 2) Thereafter, the mixture was water-cooled for 5 minutes while being crushed. 3) The sample was removed from the jig and left at room temperature (25 ° C.) for one day, and then the height h1 (mm) was measured and determined by the following equation. Shape shaping ratio (%) = (18−h1) / 18 × 100

* 6 Shape recovery rate: The vulcanized tube-shaped sponge having a height of 18 mm in FIG. 1 was left again in an oven at 180 ° C. for 5 minutes, then taken out, and taken out at room temperature (25 ° C.)
After leaving for 1 day, the height h2 (mm) was measured, and it was obtained from the following equation. Shape recovery rate (%) = h2 / 18 × 100

A recycled rubber molded article was manufactured by the following method using the tubular sponge of FIG. 1) The sponge is cut into a size of 3 mm × 3 mm × 2 mm, and is 180 ° C. which is equal to or higher than the melting point of the crystalline polypropylene contained in the raw material of the sponge for recycling.
For 3 minutes. 2) While maintaining the heat of 160 ° C. or higher, a powder of polypropylene was mixed at a ratio of 3 parts by weight with respect to 100 parts by weight of the sponge and mixed so as to adhere to the sponge surface. 3) Then, a cooling mold (2 mm × 125 mm × 125 m
m) at a cavity filling rate of 110 vol%,
By applying pressure (25 ° C. for 2 minutes) using a t-press, a recycled rubber molded product was obtained.

Table 5 shows the physical properties of the recycled rubber molded product obtained by the above method.

[Table 5] * 1 to * 3 See * 1 to * 3 in Table 4.

Examples 2 and 3 Using a Banbury mixer (manufactured by Kobe Steel Co., Ltd.) having a capacity of 4.3 liters, each rubber compounding agent was kneaded at a filling ratio of 70% for 5 minutes at a compounding ratio shown in Table 6. And got the compound.

[0075]

[Table 6] * 1 EPT rubber: Refer to * 1 in Table 1. * 2 Trade name sheath SO, manufactured by Tokai Carbon Co., Ltd. * 3 Trade name PW90, manufactured by Idemitsu Kosan Co., Ltd.

After cooling the compound obtained as described above, 1.5 parts by weight of sulfur and a vulcanization accelerator MBT (trade name: Noxeller M, manufactured by Ouchi Shinko Chemical Industry Co., Ltd.)
5 parts by weight, vulcanization accelerator ZnBDC (trade name: Noxeller BZ, manufactured by Ouchi Shinko Chemical Co., Ltd.) 0.5 part by weight, vulcanization accelerator TeEDC [trade name: Noxeller TTTE, Ouchi Shinko Chemical Industry Co., Ltd. 0.5 parts by weight and 0.75 parts by weight of a vulcanization accelerator DPTT [trade name: Noxeller TRA, manufactured by Ouchi Shinko Chemical Industry Co., Ltd.] and a 16-inch roll (roll temperature before and after: 50 ° C.) To obtain an unvulcanized rubber. Mooney viscosity of the obtained unvulcanized rubber [ML
_{1 + 4} (100 ° C.)], and t ₅ (minutes) and t ₉₀ (minutes) specified in JIS K6301 were measured. Table 7 shows the results.

The unvulcanized rubber obtained as described above was press-vulcanized at 160 ° C. for 20 minutes to prepare a vulcanized rubber sheet having a thickness of 2 mm. About the obtained vulcanized rubber, tensile strength (T _B ), elongation (E _B ), spring hardness (H _S ,
JIS A hardness) and compression set (CS) were measured.

[0078]

[Table 7] * 1 See * 3 in Table 4. * 2 See * 3 in Table 4. * 3 See * 4 in Table 4. * 4 See * 5 in Table 4. * 5 See * 6 in Table 4.

A recycled rubber molded article was produced by the following method using the shape-memory vulcanized rubber having the physical properties shown in Table 7. 1) In order to cut a defective product of shape memory vulcanized rubber produced by press vulcanization into a size of 3 mm × 3 mm × 2 mm and recycle it, the melting point is 180 ° C. or more of the polypropylene or polybutene contained in the raw material. Heated at ℃ for 3 minutes. 2) While maintaining the heat of 160 ° C., the same polypropylene powder as in Example 1 was added to 100 parts by weight of the vulcanized rubber.
They were blended in parts by weight and mixed so as to adhere to the surface of the vulcanized rubber. 3) Then, a cooling mold (2 mm × 125 mm × 125 m
m) at a cavity filling rate of 110 vol%,
The recycled rubber molding was obtained by pressurizing (25 ° C. for 2 minutes) using a t-press machine.

Table 8 shows the physical properties of the recycled rubber molded product obtained by the above method.

[Table 8]

[Brief description of the drawings]

FIG. 1A is a front view of a tubular sponge formed in an example, and FIG. 1B is a cross-sectional view thereof.

FIG. 2 is a cross-sectional view of a base used in the embodiment.

[Explanation of symbols]

 1 tubular sponge 3 base

Claims (12)

[Claims] 1. A recycled rubber molded article obtained by adding a thermoplastic resin (A) to a cut or pulverized product of a vulcanized rubber [I] and press-molding the thermoplastic resin (A) in a molten state. 2. The recycled rubber molded article according to claim 1, wherein the amount of the thermoplastic resin (A) is 0.1 to 10 parts by weight based on 100 parts by weight of the vulcanized rubber [I]. 3. The recycled rubber molded article according to claim 1, wherein the vulcanized rubber [I] is a weather strip of an automobile part, a defective product or a waste rubber generated in a rubber manufacturing process. 4. The vulcanized rubber [I] has a shape shaping ratio of 50%.
The recycled rubber molded article according to any one of claims 1 to 3, which is a shape-memory vulcanized rubber having a shape recovery ratio of 50% or more. 5. The vulcanized rubber [I] is an ethylene / α-olefin / non-conjugated polyene copolymer rubber (B) comprising ethylene, an α-olefin having 3 to 20 carbon atoms, and a non-conjugated polyene. The recycled rubber molded article according to any one of claims 1 to 4, wherein the rubber composition [II] containing the polyolefin resin (C) is a vulcanized rubber. 6. The rubber composition [II] is a composition in which particles of a polyolefin resin (C) are micro-dispersed in an ethylene / α-olefin / non-conjugated polyene copolymer rubber (B), The recycled rubber molded article according to claim 5, wherein the polyolefin resin (C) has an average dispersed particle diameter of 0.1 to 100 µm. 7. The rubber composition [II] contains 5 to 50 parts by weight of a polyolefin resin (C) based on 100 parts by weight of an ethylene / α-olefin / non-conjugated polyene copolymer rubber (B). 7. The recycled rubber molded article according to 5 or 6. 8. The polyolefin resin (C) has a melting point of 70.
The recycled rubber molded product according to any one of claims 5 to 7, wherein the molded product is a resin having a temperature of from 200 to 200 ° C. 9. After cutting or pulverizing the vulcanized rubber [I], a thermoplastic resin (A) is added, and the thermoplastic resin (A) is added.
A method for producing a recycled rubber molded article according to any one of claims 1 to 8, wherein the molded article is melt-formed and press-molded. 10. After the vulcanized rubber [I] is cut or pulverized, it is heated above the melting point of the polyolefin resin (C), and then the thermoplastic resin (A) is added to melt the thermoplastic resin (A). A method for producing a recycled rubber molded article, wherein the method is press-molded to produce the recycled rubber molded article according to any one of claims 5 to 8. 11. Heating the thermoplastic resin (A) in a mold for press molding to a temperature not lower than the melting point of the thermoplastic resin (A).
11. The method according to claim 9, wherein 12. After heating above the melting point of the polyolefin resin (C), the thermoplastic resin (A) is added while maintaining the temperature at which the thermoplastic resin (A) can be melted, and the thermoplastic resin (A) is added. The production method according to claim 10, wherein A) is melted and is not heated in a mold for press molding.