JP2001064627A - Packing for doorstop - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a packing for doorstop by using a thermoplastic elastomer that has a sufficient adhesion in a two color formation with an ABS resin. SOLUTION: The objective doorstop packing is produced by simultaneously extruding a thermoplastic elastomer composition comprising the following (a) through (c) and an ABS resin respectively from separated extruders and the extruded polymer compositions are introduced into one dice to form a fusion- bonded packing: (a) 10-50 wt.% of a hydrogenated block copolymer prepared by hydrogenating a block copolymer comprising a chain-terminal polymer block A mainly comprising at least two vinyl aromatic compounds and an intermediate polymer block B mainly comprising at least one conjugated diene, (b) 5-30 wt.% of a hydrogenated block copolymer modified with a polar group and (c) 40-50 wt.% of a thermoplastic polyurethane.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a conventional rigid PVC.
When two-color coextrusion molding of (polyvinyl chloride) and soft PVC is used, it is usually used as a substitute for rigid PVC when materials other than PVC are to be used due to environmental issues, etc. The present invention relates to a door stop packing using a flexible PVC substitute elastomer composition capable of being melt-bonded to ABS and having an appearance and airtightness comparable to PVC.

[0002]

2. Description of the Related Art Conventionally, two-color simultaneous molding (extrusion molding, rigid PVC / soft PVC) for various applications in the field of building materials and home electric appliances.
Injection molding). However, the use of PVC has been shunned due to recent environmental issues, and ABS resin is often used on the hard side as a substitute material. However, there is no suitable soft material that melts and bonds with ABS, and it is bonded at the interface. In many cases, molded articles are produced through more complicated steps such as using an agent. In this case, the total cost becomes considerably high, and PV is limited only in a limited field.
At present, the replacement from C has not progressed.

[0003]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, and makes it possible to obtain a two-color molded article with an ABS resin having a sufficient adhesive strength in a processing step similar to that of PVC. To provide a door stop packing using the novel thermoplastic elastomer composition of the present invention.

[0004]

As a result of various studies, the present inventors have found that among styrene-based elastomers known as hydrogenated block copolymers of the component a, those having a number average molecular weight of 70,000 or more are particularly desirable. In the presence of a styrenic elastomer modified with a polar group of component b as a main component, a thermoplastic polyurethane of component c is added and alloyed to exhibit good melt adhesion with ABS. It has been found that a molded article having good adhesiveness can be obtained by two-color simultaneous extrusion molding of the present invention, and the present invention has been completed.

That is, the present invention relates to the following components a, b,
This is a door-stop packing obtained by simultaneously extruding the thermoplastic elastomer composition composed of c and the ABS resin from separate extruders, introducing them into one die, and fusing and adhering them. (A) A hydrogenated block copolymer comprising at least two terminal polymer blocks A mainly composed of a vinyl aromatic compound and at least one intermediate polymer block B mainly composed of a conjugated diene compound The obtained hydrogenated block copolymer has a spring hardness (JIS K6301) of 99 or less and a number average molecular weight of 70,000 or more.
(B) a block copolymer comprising at least two terminal polymer blocks A mainly composed of a vinyl aromatic compound and at least one intermediate polymer block B mainly composed of a conjugated diene compound; An acid value of 1 to 30 mg obtained by modifying a hydrogenated block copolymer obtained by hydrogenation with a polar group.
(CH ₃ ONa) / 5~30 wt% that of g (c) Thermoplastic polyurethane 40 to 50 wt%

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The hydrogenated block copolymer used in the present invention comprises at least two terminal polymer blocks A mainly composed of a vinyl aromatic compound and at least one intermediate polymer block B mainly composed of a conjugated diene compound. Is obtained by hydrogenating a block copolymer having the structure represented by the following general formula, which is obtained by hydrogenating a block copolymer of a vinyl aromatic compound and a conjugated diene compound. A- (BA) n (1 ≦ n ≦ 5) In order to obtain a hydrogenated block copolymer elastomer composition, a hydrogenated block copolymer having a hardness of 99 or less, preferably 90 or less is used. Therefore, the content of the vinyl aromatic compound is 5 to 50% by weight, preferably 10 to 40% by weight. Further, regarding the block structure, the terminal polymer block A mainly composed of a vinyl aromatic compound is a vinyl aromatic compound polymer block or a vinyl aromatic compound containing a vinyl aromatic compound in an amount of more than 50% by weight, preferably 70% by weight or more. Having a structure of a copolymer block of a group III compound and a hydrogenated conjugated diene compound, and an intermediate polymer block B mainly composed of a hydrogenated conjugated diene compound, It has a structure of a coalesced block or a copolymer block of a hydrogenated conjugated diene compound containing more than 50% by weight, preferably 70% by weight or more of a hydrogenated conjugated diene compound and a vinyl aromatic compound. . When there are two or more polymer blocks mainly composed of a vinyl aromatic compound and two or more polymer blocks mainly composed of a hydrogenated conjugated diene compound, each of the polymer blocks may have the same structure or may be different. It may have a structure.

As the vinyl aromatic compound constituting the hydrogenated block copolymer, for example, one or more of styrene, α-methylstyrene, vinyltoluene, p-tert-butylstyrene and the like can be selected. Among them, styrene is preferred. As the conjugated diene compound before hydrogenation constituting the hydrogenated conjugated diene compound, for example, one or more selected from butadiene, isoprene, 2.3-dimethyl-1.3-butadiene and the like are selected. Among them, butadiene, isoprene and a combination thereof are preferred. Further, the molecular structure of the hydrogenated block copolymer may be linear, branched, radial, or any combination thereof. The number average molecular weight (Mn) of the hydrogenated block copolymer of the component a used in the present invention is 70.
The molecular weight distribution Mw / Mn is 10 or less (Mw: weight average molecular weight), preferably 5 or less, more preferably 2 or less. When the number average molecular weight is less than 70,000,
Sufficient strength cannot be provided. 1 molecular weight distribution
If it exceeds 0, the strength decreases. The amount of the component a is 10 to 50% by weight, preferably 20 to 50% by weight.
It is. If the amount of the component (a) is less than 10% by weight, sufficient strength and flexibility cannot be imparted. If the amount exceeds 50% by weight, fluidity is remarkably reduced, and a molded article having a good appearance after molding is obtained. I can't get it. In addition, since the hydrogenated block copolymer of the component a has a large number average molecular weight, an oil-extended product of paraffinic oil can be appropriately used for improving workability.

The modified polar group of the hydrogenated block copolymer used as the component (b) of the present invention improves the compatibility between the component (a) and the component (c). Contributes to improvement of mechanical properties. A polymer obtained by modifying the hydrogenated block copolymer of component a with maleic anhydride, an epoxy ring-containing group, or the like corresponds to this, and among them, an acid value of 1
It is preferably ₃₀ mg (CH ₃ ONa) / g. If the acid value is less than 1 mg (CH ₃ ONa) / g, a sufficient compatibility-improving effect cannot be obtained, and if the acid value exceeds 30 mg (CH ₃ ONa) / g, a decrease in strength and a deterioration in molded appearance are observed. The amount of the component b is 5 to 30% by weight, preferably 10 to 30% by weight.
25% by weight. If it is less than 5% by weight, the effect of improving the compatibility cannot be obtained, and if it exceeds 30% by weight, the strength is reduced and the appearance is deteriorated.

[0009] The thermoplastic polyurethane of the component c used in the present invention improves the heat fusion strength with ABS. Thermoplastic polyurethanes are usually made by a polyaddition reaction between a diisocyanate and a polyol. As the diisocyanate, tolylene diisocyanate, diphenylmethane-
4,4′-diisocyanate, 1,5-naphthalenediisocyanate, 4,4′-dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, and the like,
Examples of the polyol include ethylene glycol, 1,4-butanediol, 1,6-hexanediol, and poly (1,4
-Butylene adipate, poly (1,6-hexylene adipate), poly-ε-caprolactone, poly (hexamethylene carbonate), poly (oxytetramethylene) glycol, etc. But it is good. Thermoplastic polyurethanes are broadly classified into ester-based polyurethanes and ether-based polyurethanes depending on the type of polyol used. The thermoplastic polyurethane used in the present invention may be either of these. 40 to 50% by weight of component c
It is. If the amount is less than 40% by weight, a sufficient heat-sealing strength with respect to the desired ABS cannot be obtained.

[0010] In addition to the above components (a) to (c), the composition of the present invention may further comprise, if necessary, a paraffinic oil, an inorganic filler, or the like, as long as the adhesive strength with ABS is not impaired.
Inexpensive resins such as polystyrene resins and polyolefin resins can also be blended. These not only have the benefit of reducing product costs as extenders, but also actively improve quality (inorganic fillers: heat-resistant shape-preserving, flame-retardant, etc., polystyrene resins, polyolefin resins: improving processability, etc.). There is also an advantage of imparting an objective effect. As the inorganic filler, for example, calcium carbonate, carbon black,
Talc, magnesium hydroxide, mica, barium sulfate,
There are natural silicic acid, synthetic silicic acid (white carbon), titanium oxide and the like. As the carbon black, channel black, furnace black and the like can be used. Of these inorganic fillers, talc and calcium carbonate are economically advantageous and preferred. Further, as the polystyrene resin that can be used for this purpose, those obtained by a radical polymerization method or an ionic polymerization method can be suitably used, and the number average molecular weight is 5,000 to 500,000, preferably 10,000 to 2,000,000.
000, and the molecular weight distribution Mw / Mn
Is preferably 5 or less. Furthermore, as polyolefin resin, high density polyethylene, low density polyethylene,
For example, a copolymer of polyethylene and α-olefin is used. Nucleating agent, outer lubricant, inner lubricant,
UV absorbers, hindered amine light stabilizers, hindered phenolic antioxidants, coloring agents, and the like may be added.

As a method for producing the composition used in the present invention, a general method used for producing ordinary resin compositions and rubber compositions can be employed. Basically, it is a mechanical melt-kneading method, in which a single-screw extruder, a twin-screw extruder, a Banbury mixer, various kneaders, Brabender, rolls and the like are used. At this time, the order of addition of each component is not limited.For example, all components are pre-mixed by a mixer such as a Henschel mixer or a blender and melt-kneaded by the above-described kneader, or any component is pre-mixed by master batch. It is possible to employ an addition method in which the components are melt-kneaded, the remaining components are added, and the mixture is melt-kneaded. At this time, the temperature for melt-kneading can be suitably selected from 170 ° C to 300 ° C.

[0012]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. The components blended in the following examples and comparative examples are as follows. <Component a> Tuftec H1272 manufactured by Asahi Kasei Kogyo: Polystyrene-hydrogenated polybutadiene-polystyrene structure, bound styrene content 35% by weight, number average molecular weight about 120,000 (paraffin oil (Diana Process Oil PW manufactured by Idemitsu Kosan Co., Ltd. -380 [paraffinic process oil, kinematic viscosity: 381.6 cst (40 ° C),
30.1 (100 ° C.), average molecular weight 746, ring analysis value:
CA = 0%, CN = 27%, CP = 73%]) 35% by weight
Oil exhibition). <Component b> Tuftec M1913 manufactured by Asahi Kasei Kogyo Co., Ltd .: Polystyrene-hydrogenated polybutadiene-polystyrene structure, 30% by weight of bound styrene, and 10 mg (CH ₃ ONa) / g acid value by introduction of a polar group. <Component c> Pandex T50 manufactured by Dainippon Ink and Chemicals, Inc.
00V: ester-based polyurethane (diphenylmethane-
4,4'-diisocyanate / polyol).

Examples 1 and 2 and Comparative Examples 1 to 5 were prepared by thoroughly dry blending the components shown in Table 1 and then using a twin-screw kneader to adjust the resin temperature to 170 to 270 ° C. And the mixture was extruded and pelletized. The following evaluation was performed using this pellet. (1) Appearance: 0.5 mm with an extruder from this pellet
It was formed into a tape shape using a 20-mm-thick dice, and spots and rough skin were visually observed. (2) ABS adhesive strength: A 1 mm-thick plate-like molded product was separately obtained by a press using the pellet and the ABS resin, and they were overlaid and pressed again (190 ° C., preheat 5
And pressurized to 50 kgf / cm ² ) and bonded to each other, and cut into a width of 20 mm to obtain a test piece. Using this, a 180 ° peel test was performed with a universal tensile tester (unit: kgf / 20 mm). (3) Tensile strength: The pellet is rolled into a sheet, rolled into a sheet having a thickness of 2 mm by a press machine, a dumbbell is punched out of the sheet, and a tensile test is performed by a universal tensile tester according to JIS K 6301. (Unit: MPa).

The results are shown in Table 1. From these results, it can be seen that the composition obtained in the present invention is excellent in appearance, strength, and ABS heat sealability.

[0015]

[Table 1]

[0016]

According to the present invention, when a rigid PVC is replaced by an ABS resin in a door stop packing conventionally made by two-color molding using a combination of a rigid PVC and a soft PVC, the rigid PVC is replaced with a soft PVC. As a substitute material, a door-to-door packing exhibiting good ABS heat sealability and excellent appearance and strength can be obtained.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) F16J 15/10 F16J 15/10 X

Claims (1)

[Claims] 1. A thermoplastic elastomer composition comprising the following (a) to (c) and an ABS resin are simultaneously extruded from separate extruders, introduced into one die, and melt-bonded. And doorstop packing. (A) A hydrogenated block copolymer comprising at least two terminal polymer blocks A mainly composed of a vinyl aromatic compound and at least one intermediate polymer block B mainly composed of a conjugated diene compound The obtained hydrogenated block copolymer has a spring hardness (JIS K6301) of 99 or less, and a number average molecular weight of 70,000 or more.
50% by weight (b) A block copolymer composed of at least two terminal polymer blocks A mainly composed of a vinyl aromatic compound and at least one intermediate polymer block B mainly composed of a conjugated diene compound is hydrogenated. An acid value of 1 to 30 mg obtained by modifying a hydrogenated block copolymer obtained by addition with a polar group.
(CH ₃ ONa) / 5~30 wt% that of g (c) Thermoplastic polyurethane 40 to 50 wt%