JPH03166245A - Thermoplastic elastomer composition - Google Patents

Abstract

PURPOSE:To obtain the subject composition, excellent in mold releasability and readily recycled for use by containing carbon black, talc and a metal soap in a resin composition containing a polyolefin, olefinic, copolymer, etc., and crosslinking the resultant mixture with a metal oxide, etc. CONSTITUTION:The objective elastomer composition obtained by containing (B) 5-100 pts.wt. carbon black or talc and (C) 0.5-1.0 pts.wt. metal soap in (A) 100 pts.wt. total amount of (i) 5-50wt.% polyolefin, (ii) 5-50wt.% halogenated butyl rubber, (iii) 5-50wt.% olefinic copolymer rubber and (iv) 10-50wt.% mineral oil-based softener and crosslinking the resultant mixture in the presence of a crosslinking agent composed of a metal oxide or chloride.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a thermoplastic elastomer composition having excellent mechanical strength and formability, and in particular to a thermoplastic elastomer composition having good mold release properties and being easy to recycle. The present invention relates to elastomer compositions.

[Prior Art and Problems to be Solved by the Invention] Thermoplastic elastomers are widely used in automobile parts, etc., as materials that fill the intermediate region between rubber and plastic, or as substitute materials for rubber.

Reasons for this include the fact that it can be easily formed using a general plastic forming machine and that scraps can be recycled.

Such thermoplastic elastomers usually have a rubber section that is uncrosslinked or partially crosslinked, and have good formability, but they are either compositions with low tensile strength and high compression set, or fully crosslinked rubber. It can be classified as a composition with high strength but poor fluidity during injection or molding.

By the way, thermoplastic elastomers have a problem in that they are difficult to release from the mold when molded into complex shapes. As a countermeasure to this problem, it is possible to use a mold release agent, but the current situation is that a mold release agent alone cannot exhibit sufficient mold release properties.

Furthermore, when scrap is crushed for recycling, the crushed material becomes fluffy, making it difficult to feed from a hopper.

To solve these problems of thermoplastic elastomers, polyolefin resin, first rubber part and second rubber part are used.
In a thermoplastic elastomer composition containing a rubber component,
The second rubber component is cured using a curing agent that is a vulcanizing agent for the second rubber component that does not act on the first rubber component,
Furthermore, a composition has been proposed in which the second rubber component is cured to a fully vulcanized state by dynamic vulcanization in the presence of the polyolefin resin and the first rubber component (Japanese Patent Laid-Open No. 61-266).
No. 43〉. In the above publication, in a preferred embodiment, the first rubber component is BPDM, the second rubber component is halogenated butyl rubber, the vulcanizing agent is 2nO, and further an inorganic filler such as carbon black and rubber It is stated that it contains process oil for Furthermore, the above-mentioned publication describes that additives such as lubricants and anti-blocking agents may be added as additional matters.

However, even in the above-mentioned thermoplastic elastomer composition, the problem of poor release from the mold when molded into a complicated shape has not yet been satisfactorily solved. Furthermore, nothing is specifically disclosed regarding the additive system effective for improving mold release properties.

Therefore, it is an object of the present invention to have good physical strength characteristics, excellent workability, low hardness, and small compressive strain, as well as excellent shape workability, especially mold release property, and the pulverized product has a shape that is easy to recycle. An object of the present invention is to provide a thermoplastic elastomer composition having a shape that allows easy feeding from a hopper.

[Means to solve the problem]

As a result of intensive research in view of the above objectives, the present inventors used polyolefin, halogenated butyl rubber, olefin copolymer rubber, and mineral oil softener, as well as a specific filler and a specific release agent. The inventors have discovered that a composition that can solve the above problems can be obtained by adding a predetermined amount of a molding agent, and have conceived the present invention.

That is, the thermoplastic elastomer composition of the present invention has (A
) 5 to 50% by weight of polyolefin, (B) 5 to 50% by weight of halogenated butyl rubber, (C) 5 to 50% by weight of olefin copolymer rubber, and (D) 10 to 50% of mineral oil softener. Weight % and the components (A), (B), (C)
and (D), a mixture containing (B) 5 to 100 parts by weight of carbon black or talc, and (P) 0.5 to 10 parts by weight of metal soap,
It is characterized by being crosslinked in the presence of a crosslinking agent consisting of a metal oxide or metal chloride.

The present invention will be explained in detail below.

First, each component of the thermoplastic elastomer composition of the present invention will be explained.

(A>Polyolefin ethylene, propylene, 1-butene, l-hexene, 4
- A homopolymer or a copolymer of two or more olefin monomers such as -methyl-1-pentene (hereinafter referred to as A), and preferably crystalline polypropylene. As used herein, the term "crystalline polypropylene" refers to both homopolymers of propylene and copolymers with the above-mentioned olefin monomers, and the melt flow rate (V
FR, 230℃, 2.16kg load> is 0.3
-60 g/10 min, preferably 1-40 g/10 min. In the case of copolymers, the brobylene content is 6
It is 0% by weight or more. Polyolefins contribute to improving the processability, heat resistance, and mechanical strength of elastomers. In particular, crystalline polypropylene has the highest melting point among polyolefins and makes a large contribution to improving heat resistance and mechanical strength.

As the A component, the above olefin polymers may be used alone, or two or more types may be used in combination.

The content of polyolefin is 5 to 50% by weight, assuming that polyolefin + halogenated butyl rubber + olefin copolymer rubber + mineral oil softener = 100% by weight. If the polyolefin content is less than 5% by weight, the above characteristics will not be fully exhibited, and if it exceeds 50% by weight, the proportions of halogenated butyl rubber, olefin copolymer rubber, and mineral oil softener will be too low. The preferred polyolefin content is 5 to 40% by weight.

(B) Halogenated butyl rubber means halogenated inbutylene-isobrene copolymer rubber (hereinafter referred to as Ba component).Halogen content is usually 0
．． It is 5 to 4.0% by weight. Also, Mooney viscosity ML. Ya. (100℃> is 30 to 100, and the degree of unsaturation is 0.5
It is preferable that it is 4.0 mol%.

Halogenated butyl rubber is a rubber that can be easily crosslinked in the presence of metal oxides such as ZnO, and provides heat resistance, damping properties, and gas impermeability, as well as contributing to improved flexibility and rubber properties. . The content of the halogenated butyl rubber is 5 to 50% by weight, assuming that polyolefin + halogenated butyl rubber + olefin copolymer rubber + mineral oil softener = 100% by weight. If it is less than 5% by weight, the above characteristics will not be fully exhibited, and if it exceeds 50% by weight, the fluidity will decrease and it will be difficult to form the mold. The preferred content of halogenated butyl rubber is 5 to 40% by weight.

As the halogenated butyl rubber, chlorinated butyl rubber and brominated butyl rubber are preferred, and chlorinated butyl rubber is particularly preferred.

(C) Olefin copolymer rubber ethylene, propylene, ■-butene, 1-hexene, 4
- Means a copolymer rubber of two or more olefins such as methyl-pentene. Typically, they are ethylene-propylene copolymer rubber (BPR) and ethylene-propylene-diene copolymer rubber (εPDM). As the diene, non-conjugated dienes such as dicyclopentadiene, 1,4-hexadiene, cyclooctadiene, methylene norbornene, and ethylidene norbornene, or conjugated dienes such as butadiene and isobrene can be used. Particularly preferred is EPDM containing a non-conjugated diene.

The ethylene content of olefin copolymer rubber is 35 to 8
8% by weight, the iodine value and degree of unsaturation) is 30 or less, and the Mooney viscosity ML++s (at 127°C) is 5.
It is preferable that it is -300.

The olefin copolymer rubber improves the flexibility and moldability of the thermoplastic elastomer composition, and also plays the role of a binder at the phase interface between polypropylene and halogenated butyl rubber.

The content of olefin copolymer rubber is polyolefin + halogenated butyl rubber + olefin copolymer rubber +
Mineral oil softener = 5 to 50% by weight as 100% by weight
It is. If the amount is less than 5% by weight, the above characteristics will not be fully exhibited, and if it exceeds 50% by weight, the fluidity will decrease and it will be difficult to form a certain shape. The preferred content of the olefin copolymer rubber is 5 to 40% by weight.

(D) Mineral oil-based softener Mineral oil-based softeners usually weaken the intermolecular forces of the rubber during roll processing, making processing easier, and also help prevent breakup of carbon black, talc, etc. , a high boiling point petroleum distillate used to reduce the hardness of vulcanized rubber and increase its flexibility, elasticity, and shapeability.
It is classified into naphthenic type, aromatic type, etc.

The blending amount of the mineral oil softener is 10 to 50% by weight, assuming that polyolefin + halogenated butyl rubber, ten olefin copolymer rubber + mineral oil softener = 100% by weight.

Less than 10% by weight is sufficient. If the amount exceeds 50% by weight, the heat resistance and mechanical strength of the composition will decrease.
In addition, the mineral oil softener oozes out, causing adverse effects such as spoiling the appearance.

The preferred content of the mineral oil softener is 10 to 40% by weight.

In the present invention, the following fillers and metal soaps are contained in the above A to Dti.

(E) Carbon black or talc carbon black has excellent reinforcing properties for thermoplastic elastomers, and also provides properties such as oil resistance and heat resistance, suppresses deterioration, improves mold release properties, and improves the ability of crushed materials to Prevents it from becoming fluffy.

The carbon black is not particularly limited, and for example, channel black, furnace black, thermal black, acetylene black, lamp black, etc. can be used.

The average particle size of the carbon black mentioned above is 0.01 to 0.5
- is preferable, and 0.01 to 0.1 - is more preferable.

Furthermore, talc is a composite salt of magnesium oxide and silicic acid, and exhibits the same effects as carbon black. The average particle size of the above-mentioned talc is preferably 0.5 to 10.

Among the above carbon black and talc, carbon black is particularly preferred.

The blending amount of the above-mentioned carbon black or talc is 5 to 100 parts by weight based on 100 parts by weight of the total amount of A to Da components. If it is less than 5 parts by weight, sufficient effects cannot be obtained;
If it exceeds 0.00 parts by weight, it tends to be unevenly distributed in the elastomer. The preferred amount is 5 to 50 parts by weight.

(F) Metal soap Metal soap is a salt of a fatty acid, naphthenic acid, etc. and a metal other than an alkali metal, and metals other than alkali metal include alkaline earth metals, Zn, Af, CdSPb.
etc. are preferred. Particularly preferred are those having stearic acid as the acid radical, and specifically preferred are magnesium stearate, calcium stearate, zinc stearate, and the like. Metal soap has the effect of reducing the adhesion of thermoplastic elastomers and improving mold release properties, and also acts as a dispersant for carbon black or talc. Further, due to the synergistic effect with the carbon black described above, it is possible to suppress the pulverized material from becoming flocculent or agglomerating.

The amount of metal soap blended is the total amount of A to Da components: 100
The amount is 0.5 to 10 parts by weight.

0. If it is less than 5 parts by weight, sufficient effects cannot be obtained, and if it exceeds 10 parts by weight, weld marks etc. are likely to occur.
It also bleeds out onto the surface of the molded product, damaging its appearance.

(6> Crosslinking agent The crosslinking agent used in the present invention includes ZnO, Mg
Metal oxides such as B, PbO, Can, or Zn
Cj! ,,5 n Cj' 4 and other metal chlorides. Preferably, ZnO is used.

The above crosslinking agents, including ZnO, crosslink the halogenated butyl rubber. In order to sufficiently crosslink the halogenated butyl rubber, the amount of the above-mentioned crosslinking agent used must be from component A to component D.
It is preferable to use 1 to 10 parts by weight per 1 part by weight of 100 parts by weight in total. A more preferable range is 1 to 5 parts by weight.

In the present invention, in addition to the above-mentioned crosslinking agent, N,N'-diethylthiourea, di-0-tolylguanidine, dipentamethylenethiuram tetrasulfide ethylene trithiocarbonate, 2-mercaptobenzothiazole, penzothiazole disulfide, N-7 phenyl-β-naphthrylamine, tetramethylthiuram disulfide, zinc diethyldithiocarbamate, zinc dibutyldithiocarbamate, zinc dimethyldithiocarbamate, and the like may be used. Also G o − } U
Luguanidine borate (for example, manufactured by Noxela PR Ni-Ouchi Shinko) can also be used. Note that two or more kinds of the above substances may be contained. In addition, the crosslinking aids include components A to D in total.
It is preferable to use 1 part by weight or more based on 100 parts by weight of the components in total. More preferably, it is 1 to 5 parts by weight.

(H) Other components In addition, as necessary, antioxidants, ultraviolet absorbers, stabilizers such as metal deterioration inhibitors, antistatic agents, electrical property improvers,
Additives such as flame retardants and pigments can be added.

The thermoplastic elastomer composition of the present invention can be produced by mixing the components described above and dynamically heat-treating, that is, melt-kneading.

As the kneading device, conventionally known devices such as open mixing rolls, closed Banbury mixers, extruders (including twin-screws), 21-goo, continuous mixers, etc. can be used. In the present invention, a preferred method for mixing and kneading each component is to mix each component A to F and
Knead for 5 minutes, then add the crosslinking agent and other ingredients, and knead for 2 to 20 minutes. The kneading temperature is preferably set appropriately depending on the melting point of the polyolefin, halogenated butyl rubber, olefin copolymer rubber, etc.

The composition of the invention thus obtained can be easily shaped using equipment used for conventional thermoplastics and is suitable for blow molding, extrusion shaping, calendar shaping and injection molding. .

[For production]

In the present invention, a polyolefin, halogenated butyl rubber, olefin-based copolymer rubber, and mineral oil-based softener are blended with a predetermined amount of carbon black or talc and metal soap, and a metal oxide or metal chloride is used. Since it is crosslinked by adding a crosslinking agent, it has good physical strength characteristics, improves mold release properties, and also makes it easy to feed the crushed product from a hopper during recycling.

The reason why such an effect is obtained is not necessarily clear, but because the halogenated butyl rubber is selectively crosslinked among the two types of rubber components, it becomes a thermoplastic elastomer that is flexible and has good physical strength properties. In addition, the metal soap improves the dispersibility of the filler carbon black or talc, and due to their synergistic effect, the mold release property is significantly improved compared to the case of using only a mold release agent. The crushed material does not become fluffy (improved crushing characteristics)
It is thought that this is because the adhesion of the crushed material itself is prevented.

〔Example〕

The present invention will be explained in further detail by the following examples.

In each Example and Comparative Example, the following ingredients were used as raw materials and various additives.

(1) Component A ■Propylene-ethylene block copolymer (BPP): Tonen Petrochemical ■IJ rBJ315 J, melt flow rate (VFR, 230 ℃, 2.16k
g load) 15g/10 minutes.

■Propylene homobolymer (HPP): Tonen Petrochemical ■
manufactured by rJ 215 J, melt flow rate (IJF
R, 230℃, 2.16kg load) 15g/
10 minutes.

(2) B t min Chlorinated butyl rubber (Ci2+1R): Exxon Chemical @ “Chlorobutyl 1066J, Mooney viscosity ML
,. ．． (100°C>55, chlorine content 2% by weight, degree of unsaturation 2% by mole.

■ Brominated butyl rubber (BrllR): Promobutyl 2244J, manufactured by Exxon Chemical ■, Mooney viscosity Ml
, +-a (+25°C>47, bromine content 2% by weight, degree of unsaturation 2 mol%.

(3) Component C: ethylene-propylene-diene copolymer rubber (EPDM
): Vistaron 3777J, manufactured by Exxon Chemical ■, Mooney viscosity ML, .1, (127°C) 45, ethylene content 6
6% by weight, diene component; ethylidene norbornene, iodine value 18.

(4) D-bun Paraffin-based process oil softener Idemitsu rPW380J Pour point: -15°C.

(5) E precepts ■Carbon black: Tokai Electrode Q @ "SEAST SO." Talc Takehara Chemical Co., Ltd. "P-talc" (6) F component Magnesium stearate (St-Mg): Sakai Chemical Co., Ltd. ■ r#1000 J.

(7) G component ■Crosslinking agent: ZnO (manufactured by Sakai Chemical Industry ■No. 3) ■Crosslinking auxiliary agent: Dicatechol borate of di-0-tolylguanidine (manufactured by Noxela PRJ Ouchi Shinko Kagaku Kogyo ■, hereinafter referred to as "crosslinking auxiliary agent") ).

Examples 1 to 6 Polybropylene, halogenated butyl rubber, EPDM, softener, carbon black or talc, and magnesium stearate were blended in the proportions shown in Table 1. In Table 1, the blending amounts of each of the above ingredients are expressed in weight % for polypropylene, halogenated butyl rubber, EPDM, and softener.

For ingredients other than the above, the total of the above minutes is 100
Expressed in parts by weight (PHR).

This formulation was mixed using a Banbury mixer at 165
After preliminary melt-kneading at 1 to 5 minutes at 175 °C, 1 part by weight of ZnO and crosslinking aid were added to a total of 100 parts by weight of polypropylene, halogenated butyl rubber, and EPDM1 softener, and the mixture was further heated at 175 °C. The mixture was melt-kneaded for 2 to 10 minutes.

This kneaded material was formed into a sheet by injection molding, and then cut into pellets. Each test piece was molded from the obtained left by injection molding, and the following tests were conducted.

The test method was as follows.

(1) MFR: JIS K7210, load 1
0kg, 230℃.

(2) Hardness (JIS A): JIS κ6310. (3
) Tensile strength (kg/cm2): JIS K6310
No. 3 dumbbell, tensile speed 500mm/min.

(4) Tensile elongation (%): JIS κ6310.

(5) Tear strength: JIS κ6310, B type, tensile speed 500 m+a/min.

(6) Compression set: JISκ6310, 70℃×22
time, 25% compression.

(7) Grinding characteristics: Blow-shaped products (bellows) and paris were pulverized using a pulverizer, and the pulverization characteristics were evaluated by the following method.

When the material is supplied from the hopper to the extruder, the ratio of the unused round pellets to the pulverized material (weight % of the pulverized material) is as follows: ◎: The material can be supplied without problems even if it is 90% by weight or more.

○: Can be supplied without problems at 50% by weight or more and less than 90% by weight.

Δ: Can be supplied without problems at 30% by weight or more and less than 50% by weight.

×: Can be supplied without problems at less than 30% by weight.

(8) Mold releasability: During the blow molding of the bellows, the mold release rate of the bellows from the mold (during 100 blow molding cycles,
Evaluation was made based on the value of the percentage of mold release without problems.

◎: 95% or more.

○: 80% or more and less than 95%.

Δ: 50% or more and less than 80%.

×: Less than 50%.

The results are also shown in Table 1.

Comparative Examples 1 to 3 Example 1 except that both the filler (carbon black or talc) and the metal soap (magnesium stearate) and either one of them were not added.
A test piece was prepared using the same method as above. Tests (1) to (8) were conducted on the obtained test piece in the same manner as in Example 1. The results are also shown in Table 1.

As is clear from Table 1, the thermoplastic elastomer composition of the present invention has sufficiently high mechanical strength and excellent crushability and mold release properties. On the other hand, the thermoplastic elastomer compositions of Comparative Examples in which metal soap and/or carbon black or talc were not used had poor crushability and mold release properties.

In particular, in the case of Comparative Example 2 in which only the metal soap among carbon black or talc (filler) and metal soap (mold release agent) was added, the crushing properties were poor and the mold release property was also not sufficient. Furthermore, in the case of Comparative Example 3 in which only carbon black was added, the mold release properties were poor and the crushing properties were also not sufficient. This shows that the combination of metal soap and carbon blank or talc improves the mold releasability and pulverization properties.

〔Effect of the invention〕

The composition of the present invention has sufficient mechanical strength because metal soap and carbon black or talc are added to the polyolefin, chlorobutyl rubber, olefin copolymer rubber, and mineral oil softener. It is large and has excellent mold releasability, and furthermore, it is easy to feed the crushed product from a hopper etc. when recycling it.

The composition of the present invention is well-balanced in terms of properties such as flexibility and strength, and has good mold releasability.
It can be easily formed into cable outer coats, grommets, cable protectors, etc. by blow molding or extrusion molding. Moreover, since the composition of the present invention can be easily recycled, it is also excellent in terms of economy.

Applicant: Tonen Petrochemical Co., Ltd.

Claims (5)

[Claims] (1) (A) 5-50% by weight of polyolefin, (B) 5-50% by weight of halogenated butyl rubber, (C) 5-50% by weight of olefin copolymer rubber, (D) Mineral oil softener 10 to 50% by weight of the agent and the above components (
For a total of 100 parts by weight of A), (B), (C) and (D), (E) 5 to 100 parts by weight of carbon black or talc, and (F) 0.5 to 10 parts by weight of metal soap. A thermoplastic elastomer composition characterized in that it is obtained by crosslinking a mixture containing the following in the presence of a crosslinking agent comprising a metal oxide or a metal chloride. (2) The thermoplastic elastomer composition according to claim 1, wherein the polyolefin is polypropylene. (3) In the thermoplastic elastomer composition according to claim 1 or 2, the halogenated butyl rubber has a Mooney viscosity ML_1_+_8 (100°C) of 30 to 100 and a halogen content of 0.5 to 4.0% by weight. , the degree of unsaturation is 0
．． A thermoplastic elastomer composition characterized in that the content is 5 to 4.0 mol%. (4) The thermoplastic elastomer composition according to any one of claims 1 to 3, wherein the halogenated butyl rubber is chlorinated butyl rubber or brominated butyl rubber. (5) The thermoplastic elastomer composition according to any one of claims 1 to 4, wherein the crosslinking agent is ZnO.