CA2058285C - Two-layer thermoplastic elastomer sheet - Google Patents
Two-layer thermoplastic elastomer sheet Download PDFInfo
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- CA2058285C CA2058285C CA002058285A CA2058285A CA2058285C CA 2058285 C CA2058285 C CA 2058285C CA 002058285 A CA002058285 A CA 002058285A CA 2058285 A CA2058285 A CA 2058285A CA 2058285 C CA2058285 C CA 2058285C
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- thermoplastic elastomer
- layer
- copolymer rubber
- weight
- sheet
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B25/00—Layered products comprising a layer of natural or synthetic rubber
- B32B25/14—Layered products comprising a layer of natural or synthetic rubber comprising synthetic rubber copolymers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B25/00—Layered products comprising a layer of natural or synthetic rubber
- B32B25/04—Layered products comprising a layer of natural or synthetic rubber comprising rubber as the main or only constituent of a layer, which is next to another layer of the same or of a different material
- B32B25/042—Layered products comprising a layer of natural or synthetic rubber comprising rubber as the main or only constituent of a layer, which is next to another layer of the same or of a different material of natural rubber or synthetic rubber
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
- C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
- C08L23/04—Homopolymers or copolymers of ethene
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
- C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
- C08L23/10—Homopolymers or copolymers of propene
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
- C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
- C08L23/16—Elastomeric ethene-propene or ethene-propene-diene copolymers, e.g. EPR and EPDM rubbers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2250/00—Layers arrangement
- B32B2250/24—All layers being polymeric
- B32B2250/248—All polymers belonging to those covered by group B32B25/00
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2307/00—Properties of the layers or laminate
- B32B2307/30—Properties of the layers or laminate having particular thermal properties
- B32B2307/306—Resistant to heat
- B32B2307/3065—Flame resistant or retardant, fire resistant or retardant
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2605/00—Vehicles
- B32B2605/08—Cars
Abstract
Disclosed is a two-layer thermoplastic elastomer sheet comprising a skin layer [I] and a reverse surface layer [II], each layer being composed of a thermoplastic elastomer containing a polyolefin resin (A) and an .alpha.-olefin copolymer rubber (B), wherein a difference [(I B) - (II B)]
between the amount (I B) of the .alpha.-olefin copolymer rubber (B) contained in the thermoplastic elastomer of the skin layer (I) and the amount (II B) of the .alpha.-olefin copolymer rubber (B) contained in the thermoplastic elastomer of the reverse surface layer (II) is in the range of 5 to 85 parts by weight. The two-layer thermoplastic elastomer sheet of the invention is excellent in vacuum forming properties and can provide molded products excellent in the soft touch and having appearance of softness, appearance of flexibility and appearance of warmth. The sheet of the invention can be widely used for interior automotive trim such as an instrument panel.
between the amount (I B) of the .alpha.-olefin copolymer rubber (B) contained in the thermoplastic elastomer of the skin layer (I) and the amount (II B) of the .alpha.-olefin copolymer rubber (B) contained in the thermoplastic elastomer of the reverse surface layer (II) is in the range of 5 to 85 parts by weight. The two-layer thermoplastic elastomer sheet of the invention is excellent in vacuum forming properties and can provide molded products excellent in the soft touch and having appearance of softness, appearance of flexibility and appearance of warmth. The sheet of the invention can be widely used for interior automotive trim such as an instrument panel.
Description
20~~~8~
'l W0-I~AYI~_R I'tll;$L~2~8.~'i_'-!C I,Lp~;I;.QMG1~_.allldl:~:l FIEhD OF THE II1V :N'~~
The present invention relates to a two-:Layer thermoplastic elastomer sheet. More particularly, t:he invention relates to a two-layer therrnop.last::i.c: e.l<x:~tomer sheet which is excellent in vacuum forming properLie:~ and can provide molded products of excelaent in the s<.~fl.
touch..
SACK ~ROU~p OI' TI1L1..~~LQI9.
Polyvinyl chloride (PVC) resins have been hermt:ofore widely used as materials for interior automot.:i ve t_ r i.rn.
However, the automotive trim made of the pol.yv:i.nyl c:lrloride resins have problems in various properties such a::> h<:at resistance, low-temperature resistance, heat aca.i.ncy characteristics, light resistance, anti-fogg:Lng prui>c:rties, odor development, lack of the soft touch anti c:hcat:w-:lookinc~
appearance. For this reason, polyole:Ein the.rnu>plu:~t:i.c:
elastomers excellent in those properties are pa:i.d rrnnc:h attention as replacements of the polyvinyl. c:h:loriclc: .resins.
In the case of using the pol.yolefin the.r°mopl.a:>tic elastomer for a vacuum forming sheet, a rubber content in the polyolefin thermoplastic elast:omer needs t.o b~ :ro:duced from the viewpoint of vacuum forming propert:i.e::>. 1(caw~ver, if a sheet made of the polyolefin the:rmoplast:Lc: a l.ust:omer
'l W0-I~AYI~_R I'tll;$L~2~8.~'i_'-!C I,Lp~;I;.QMG1~_.allldl:~:l FIEhD OF THE II1V :N'~~
The present invention relates to a two-:Layer thermoplastic elastomer sheet. More particularly, t:he invention relates to a two-layer therrnop.last::i.c: e.l<x:~tomer sheet which is excellent in vacuum forming properLie:~ and can provide molded products of excelaent in the s<.~fl.
touch..
SACK ~ROU~p OI' TI1L1..~~LQI9.
Polyvinyl chloride (PVC) resins have been hermt:ofore widely used as materials for interior automot.:i ve t_ r i.rn.
However, the automotive trim made of the pol.yv:i.nyl c:lrloride resins have problems in various properties such a::> h<:at resistance, low-temperature resistance, heat aca.i.ncy characteristics, light resistance, anti-fogg:Lng prui>c:rties, odor development, lack of the soft touch anti c:hcat:w-:lookinc~
appearance. For this reason, polyole:Ein the.rnu>plu:~t:i.c:
elastomers excellent in those properties are pa:i.d rrnnc:h attention as replacements of the polyvinyl. c:h:loriclc: .resins.
In the case of using the pol.yolefin the.r°mopl.a:>tic elastomer for a vacuum forming sheet, a rubber content in the polyolefin thermoplastic elast:omer needs t.o b~ :ro:duced from the viewpoint of vacuum forming propert:i.e::>. 1(caw~ver, if a sheet made of the polyolefin the:rmoplast:Lc: a l.ust:omer
- 2 -having a low content of rubber is subjected to vacnunr forming, the resulting molded product is rig:i.<~ and :lacking in soft touch (softness).
~g,-rr. ~m of TEtF IlY~l=L7:QI~
The present invention is to solve the ai~ove-mmr~t_ionect problems existing in the prior arts, and it:. :i> an <W-ject oL
the invention is to provide a two-layer t-hermopla:;l:ic elastomer sheet which is excellent in vacuum form:i.rpl .LO properties and can produce molded products exce:l.icW: .in the:
soft touch.
~L~I&$.Y OF TtIE INVEN'PTOI9.
There is provided by the present invention a two-layer thermoplastic elastomer sheet comprising a sk:i.n .layer [I]
and a reverse surface layer [II], wherein:
the skin layer i.s composed of a thermop:l.a.rst:i<:
elastomer containing a polyolefin resin (A) i.n an amount o.f:
1 to 85 parts by weight and an Cc-olefin <:oF.~c>:tymc.r ~wWber (B) in an amount of 99 to 15 parts by we:iglrt, t:ot<r 1. amount of (A) and (B) being 100 parts by we:i.ght;
the reverse surface layer [II] is composed oi: a thermoplastic elastomer containing a polyo:lc:Fin rea:in (A) in an amount of 6 to 90 parts by weight and an cx-o l.c:fi.n copolymer rubber (B) in an amount of 94 to :10 part::, by weight, total amount of (A) and (t3) bein<~ 700 i>arL::c ly weight; and a dif.Eerence [ (I~) - (III) ] between the auumoil. (I~i) o.f the cx-olefin copolymer rubber (i3) contained :i.n tLm thermoplastic elastomer of the skin layer (T) and t.hc;
amount (Tlir) of the oc-olefin copo:l.ymer rubber (i3) contained in the thermoplastic elastomer of the reverse: surf<~cc: layer (II) is in the range of 5 to X35 parts by we.iglU..
If a light stabilizer i.s added to the t:hc:rmop:lustic elastomer constituting the skin layer [T] arn<i a E:1<.~me-retardant is added to the thermoplastic elastomer constituting the reverse surface layer [II], t.h<:r~ can be obtained a two-layer thermoplastic elastomur sheet: capable of producing a molded product which is excellent :i.n .l.i.ght resistance and flame retardance and is :free from occurrence of bleedout.
At the same time the two-layer thermop.l.a:~t::i.c c.:i.astomer sheet can provide molded products having exce:l:l.ent. vacuum forming properties and the soft touch.
DFTAThED D>SGRIPTTON Of Til>a -.tjyyJ_~~S2il The two-layer thermoplastic elastomer :>heet of the present invention is concretely described below.
The two-layer thermoplastic elastomer ;sheet of: the invention comprises a skin layer [I] and a reverse, surface layer [II], and these layers are <~omposed <>it:hermcy.>lasti.c - ~ - 20~~~~~
elastomers (TPE) of different kinds which d:i.f.'fe.r i.n the amounts of a polyolefin resin (A) and an Oc-ol.ef:in copolymer rubber (B) contained therein.
Examples of the polyolefin resins (A) :incl.ude;
homopolymers of ethylene or propy:l.ene, and copol.yrrrc:rs of ethylene or propylene with a small amount o.f: ot:he.r polymerizable monomer (e. g., propylene-ethya.ene: copolymer, propylene-1-butene copolymer, propylene-:L-hexe:rre c:of.rol.ymer, propylene-4-methyl-1-pentene copolymer) . A:> the a:rt>cwe-mentioned other polymerizable monomers of a snral.l. amount, there can be mentioned vinyl acetate, ethyl ac:ryl.aate and methacrylic acid. In the invention, the me:l.t :i.ndex (ASTM-D-1238-65T, 230 °C) of the polyolefin resin is preferably within the range of 0.1 to 100, more prefer<rbl.y 5 k:o 50.
As the polyolefin resin, a mixture of polyethylene (particularly, low-density polyethylene) and pc>:l.ypropylene having a mixing ratio of 10/90 to 70/30 (palyethylene/polypropylene) can be used for the pu~~pose of enhancing forming properties (fornrab:ility) and .ue;~ i.utance of damage of the resulting sheet.
The cx-olefin copolymer rubber. (B) empl.oy<xh:Lc. .i.rr the invention is an amorphous elastomeric copol.yme:r. containing w olefin as a host component, such as ethyleno-~>:ropy:l.c:ne copolymer rubber, propylene-ethylene copo:lymex- :ru1>k~c:r., ethylene-propylene non-conjugated dime copo:Lymer rubber, propylene-ethylene non-conjugated dime copolymer robber, ethylene-butadiene copolymer rubber and propy:l.ene-t>ictadiene copolymer rubber. Further, 'the cx-olefin co~ao:l.ycner .rwbber is a rubber which is reduced in flowabili.ty o:r :Lo~~~~>
flowability by the crosslinking when it i.s mixed w:it.h organic peroxide and kneaded therewith under hE:at.i.rcg . The non-conjugated diene is a generic name to dicyclopentadiene, 1,4-hexadiene, dicycloctadie;ne, methylene norbornene, ethylidene norbornene, etc.
Of these copolymer rubbers, ethylene-propylene non-~~
conjugated diene copolymer. rubber, particular:Ly et:hylene-propylene-ethylidenenorbornene copolymer rubber., i.:~
preferably used in the invention, because <v l.he:rmol>:lastic elastomer molded product excellent in heat res:i.stan<.:e, tensile characteristics and impact resilience c:an be obtained. The Mooney viscosity [MLI~n (100 °C) ] of t:he copolymer rubber is preferably in the range of 10 t:o 120, more preferably 40 to 80. In 'the case of using a copolymer rubber having Mooney viscosity of the above range, a thermoplastic elastomer product having h:i.gh t:ensi 1. c:
characteristics can be obtained. The iodine va:l.ue (degree of unsaturation) of the copolymer rubber is prc::terab:Ly not more than 16. In the thermoplastic elastomer c:onst:i.tuting the skin layer [I] of the two-layer thermop:l.ast.ic e:lastomer ,:
sheet of the invention, the po:Lyol.ef.in r.esira (A) i.~ used :in an amount of 1 to 85 parts by weight, pre:Eer-ab:l.y 20 to 80 parts by weight, more preferably 30 to 50 parts by weight, and the Oc-olefin copolymer rubber (B) is used .in an amount of 99 to 15 parts by weight, preferably 80 to 20 parts by weight, more preferably 70 to 50 parts by we:i.ght, per 100 parts by weight of 'the sum of the po:Lyolef:i.n resin (A) and the Ot-olefin copolymer rubber (B).
In the thermoplastic elastomer constituti.nd Lhe reverse surface layer [II] of the two-layer t:hermop:Lastic elastomer sheet of the invention, the polyolel::i.n re:~:i.n (A) is used in an amount of 6 to 90 parts by we:i.ght:, f:>.rc:a:erabl.y 20 to 80 parts by weight, more prefe.rabl.y 30 t.o 50 parts by weight, and the cx-olefin copolymer rubber (k3) is used in an amount of 9A to 10 parts by weight, preferably 80 to 20 parts by weight, more preferably 70 to 50 parts by weight, per 100 parts by weight of the sum of the po:Lyolet:i.n resin , (A) and the oc-olefin copolymer rubber (B) . 'Phe total amount of the polyolefin resin (A) and the cx-o:l.efin copolymer rubber (B) is 100 parts by weight. 11 dif.Eerenc~
[ (In) - (III) ] between the amount (Irs) of the cx-ol.e.Gin copolymer rubber (B) contained in the thermopl.ast:i.c elastomer of the skin layer (I) and the amo~:mt (I:fis) of the cx-olefin copolymer rubber (B) contained in the thermoplastic elastomer of the reverse surface layer (II) is in the range of 5 to 85 parts by weight, preFerab:Ly 10 to 70 parts by weight, more preferably 15 l0 50 parts by weight.
When two kinds of the thermoplastic elast:omers having a difference of the above range in the content o.t' k:tre (x-olefin copolymer rubber (B) are used, a two-:layer sheet having high vacuum forming properties and capab:l.e o:l producing a molded product especially soft in k.he touch In the invention, the thermoplastic el.asi:omer~ of the skin layer [T] and the reverse surface layer [:II]
constituting a two-layer sheet may contain a peroxi.cte non-crossl.inkable hydrocarbon gum rubber (C) and/or a mineral oil softening agent (D) in addition to the po:l.yo.lc:fin resin (A) and the oc-olefin copolymer rubber (B).
The peroxide non-crosslinkable hydrocarbon gi.rm rubber (C) employable in the invention is a gum rubber: of hydrocarbon type which is not crosslinked and is not reduced in flowability even when it is mixed with peroxide and kneaded therewith under heating. Examples of the gum rubber include pol.yisobutylene, butyl rubber (:k:l:R) , propylene-ethylene copolymer rubber having propylene content of not less than 70 o by mole, and atact:ic polypropylene. Of these, polyisobutylene and k~utyl. rubber are most preferred because of good performance and easy handling.
The peroxide non-crosslinkab:le hydroctrrbon guru :rubber (C) shows an effect to improve flowability of <:r thermoplastic elastomer composition. Tn the invent::ion, ,.
suitably employed is a peroxide non-crosslinkab.le hydrocarbon gum rubber having Mooney viscosity [ML,.~,~ (100 °C)] of not more than 60.
The peroxide non-crosslinkable hydrocarbon gum rubber (C) is used in the invention in an amount o:f 5 to _1.00 parts by weight, preferably 10 to 50 parts by weight, tTlUre preferably 15 to 40 parts by weight, per 100 parts by weight of the sum of the polyolefin resin (A) and the Cc-olefin copolymer rubber (B).
The mineral oil softening agent (D) emp:Loyable in the invention is a high-boiling petroleum cut which is generally used for mitigating intermolecular force of rubber to facilitate processing of rubber in the roll.-processing procedure, assisting di.spersibili.ty of carbon black, white carbon, etc. added as a filler, o.r reducing rigidness of vulcanized rubber to increase fl.exib:ili.ty and elasticity thereof. The mineral oil softening agent is classified into paraffin type, naphthene type, aromatic type, etc.
A molded product obtained from a thermopl.ast:i.c elastomer composition containing the naphthene type mineral oil softening agent shows less surface tackiness as compared with a molded product obtained from a thermoplastic elastomer composition containing paraffin type mineral oil softening agent, so that t:he naphthene type mineral oil softening agent is more pre:Eerab:l.y used in the invention than the paraffin type mineral. oil softening agent.
In the invention, the mineral ail soften:i.ng agent (D) is used in an amount of 5 to 100 parts by wei<jht, preferably 10 to 80 parts by weight, more preferab7.y 20 to 70 parts by weight, per 100 parts by weight. of the sum of the polyolefin resin (A) and the oc-olefin copolymer rubber (B) .
The two-layer thermoplastic elastomer sheet ol: the invention may contain other additives, provided float the addition of the additives does not mar the object of the invention. Examples of the additives include po:lyalefin plastics such as high-density polyethylene, :intermediate density polyethylene, low-density polyethylene, isotactic polypropylene and propylene-a-olefin copolymer; inorganic fillers such as calcium carbonate, calcium silicate, clay, kaolin, talc, silica, diatomaceous earth, mica powder, asbestos, alumina, barium sulfate, aluminum su:l:Eate, calcium sulfate, basic magnesium carbonate, molybdenum disulfide, graphite, glass bulb and shirasu bal._Loon; and colorants such as carbon black, titanium oxide, zinc white, blood red, ultramarine blue, Milori blue, azo pigment, nitroso pigment, lake pigment and phthalocyanine pigment.
Further, the two-layer thermoplastic el.astomer sheet of the invention there may be used known heat stab:i:Lizers such as heat stabilizers of phenol type, su:l.fi.te type, ~~~8~~~
phenylalkane type, phosphite type and amine type, ag:ing-inhibiting agent, weathering stabilizer, ant:i_staL.i.c agent, metallic soap, and lubricant such as wax. 'they can be added in such an amount as generally used for conventional polyolefin resins or oc-olefin copolymer rubbers.
If a light stabilizer such as ul.traviol.et absorl>:ing agent, light absorbing agent and hindered amin<:s is added to the thermoplastic elastomer constituting the skin :Layer [I] of the two-layer thermoplastic elastomer sheet: of the invention and a flame-retardant is added to the thermoplastic elastomer constituting the reverse surface layer [IT] thereof, there can be obtained a two-la°ryer thermoplastic elastomer sheet capable of provicLinc~ a molded product which is excellent in light resistance and flame retardance and free from occurrence of bleedout that causes marked deterioration in merchandise value.
However, if the light stabilizer and ttie .P7.amc:-retardant are together added to and allowed to present in the same thermoplastic elastomer according t:o L:he prior art, occurrence of bleedout could not be preverstecl.
There is no specific limitation on the :Li<~ht stabilizer and the flame-retardant employab:l.e a.n the;
invention, provided that they are generally used for conventional polyolefin thermoplastic elastomex~s.
Concrete examples of the light stabili.zer.s prefor~ably used in the invention include antioxidants of hindered - 1:1 -phenol type represented by pentaerythritol-tetrak:is[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] and oc:tadecy:l.-3-(3,5-di-t-butyl-~1-hydroxyphenyl)propionate; and l.i.ght stabilizers of hindered amine type represented by bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate.
In the case of using the above-mentioned l.i.ght stabilizers of hindered amine type, light stabilizers of benzotriazole type represented by 2-(3-t-butyl.-5-methyl-2-hydroxyphenyl)-5-chlorobenzotri.azole. can be employed .in combination. The antioxidants of hindered phenol type and the light stabilizers of hindered amine type uay be used singly or in combination.
The amount of the light stabilizer used i.n the invention is generally in the range of 0.07. to 0.3 phr, preferably 0.05 to 0.2 phr.
Concrete examples of the flame-retardants preferably used in the invention include inorganic flame-retarciants represented by antimony oxide and aluminum hydroxide; and halogen type flame-retardants represented by decabromodiphenyl ether and chlorinated polyethy:lene:.
The organic flame-retardant and the ha7.ogen type flame-retardant can be employed singly or :i.n comb:i.nal,ion.
When the inorganic flame-retanddnt i.s used, the amount of the flame-retardant used in the i.yvention i.:~ gene.>:ally in the range of 10 to 200 phr, preferab~.y 5 to 150 plr.
When the halogen type flame-retardant was used, the amount ~~~~28~
of the flame-retardant used is generally :in the range of 10 to 100 phr, preferably 25 to 55 ph r.
The thermoplastic elastomer as ment:i.oned above can be obtained, for example, by dynamically heat-treat:i.n<~ a blend of the above-mentioned components in the presence o.L
organic peroxide to be partially crosslinked.
The expression "dynamically heat-treat:i.ng a blend"
means that a blend is kneaded in the molten state of dissolution.
Concrete examples of organic peroxides employable for preparing the thermoplastic elastomer in the invention include dicumyl peroxide, di-tart-butylperoxi.de, 2,5-dimethyl-2,5-di-(tart-butylperoxy)hexane, 2,5-dirnethyl-2,5-di(tert-butylperoxy)hexine-3, 1,3-bis(tert-butylperoxyisopropyl)benzene, l,1-bis(tert-butylpe.roxy)-
~g,-rr. ~m of TEtF IlY~l=L7:QI~
The present invention is to solve the ai~ove-mmr~t_ionect problems existing in the prior arts, and it:. :i> an <W-ject oL
the invention is to provide a two-layer t-hermopla:;l:ic elastomer sheet which is excellent in vacuum form:i.rpl .LO properties and can produce molded products exce:l.icW: .in the:
soft touch.
~L~I&$.Y OF TtIE INVEN'PTOI9.
There is provided by the present invention a two-layer thermoplastic elastomer sheet comprising a sk:i.n .layer [I]
and a reverse surface layer [II], wherein:
the skin layer i.s composed of a thermop:l.a.rst:i<:
elastomer containing a polyolefin resin (A) i.n an amount o.f:
1 to 85 parts by weight and an Cc-olefin <:oF.~c>:tymc.r ~wWber (B) in an amount of 99 to 15 parts by we:iglrt, t:ot<r 1. amount of (A) and (B) being 100 parts by we:i.ght;
the reverse surface layer [II] is composed oi: a thermoplastic elastomer containing a polyo:lc:Fin rea:in (A) in an amount of 6 to 90 parts by weight and an cx-o l.c:fi.n copolymer rubber (B) in an amount of 94 to :10 part::, by weight, total amount of (A) and (t3) bein<~ 700 i>arL::c ly weight; and a dif.Eerence [ (I~) - (III) ] between the auumoil. (I~i) o.f the cx-olefin copolymer rubber (i3) contained :i.n tLm thermoplastic elastomer of the skin layer (T) and t.hc;
amount (Tlir) of the oc-olefin copo:l.ymer rubber (i3) contained in the thermoplastic elastomer of the reverse: surf<~cc: layer (II) is in the range of 5 to X35 parts by we.iglU..
If a light stabilizer i.s added to the t:hc:rmop:lustic elastomer constituting the skin layer [T] arn<i a E:1<.~me-retardant is added to the thermoplastic elastomer constituting the reverse surface layer [II], t.h<:r~ can be obtained a two-layer thermoplastic elastomur sheet: capable of producing a molded product which is excellent :i.n .l.i.ght resistance and flame retardance and is :free from occurrence of bleedout.
At the same time the two-layer thermop.l.a:~t::i.c c.:i.astomer sheet can provide molded products having exce:l:l.ent. vacuum forming properties and the soft touch.
DFTAThED D>SGRIPTTON Of Til>a -.tjyyJ_~~S2il The two-layer thermoplastic elastomer :>heet of the present invention is concretely described below.
The two-layer thermoplastic elastomer ;sheet of: the invention comprises a skin layer [I] and a reverse, surface layer [II], and these layers are <~omposed <>it:hermcy.>lasti.c - ~ - 20~~~~~
elastomers (TPE) of different kinds which d:i.f.'fe.r i.n the amounts of a polyolefin resin (A) and an Oc-ol.ef:in copolymer rubber (B) contained therein.
Examples of the polyolefin resins (A) :incl.ude;
homopolymers of ethylene or propy:l.ene, and copol.yrrrc:rs of ethylene or propylene with a small amount o.f: ot:he.r polymerizable monomer (e. g., propylene-ethya.ene: copolymer, propylene-1-butene copolymer, propylene-:L-hexe:rre c:of.rol.ymer, propylene-4-methyl-1-pentene copolymer) . A:> the a:rt>cwe-mentioned other polymerizable monomers of a snral.l. amount, there can be mentioned vinyl acetate, ethyl ac:ryl.aate and methacrylic acid. In the invention, the me:l.t :i.ndex (ASTM-D-1238-65T, 230 °C) of the polyolefin resin is preferably within the range of 0.1 to 100, more prefer<rbl.y 5 k:o 50.
As the polyolefin resin, a mixture of polyethylene (particularly, low-density polyethylene) and pc>:l.ypropylene having a mixing ratio of 10/90 to 70/30 (palyethylene/polypropylene) can be used for the pu~~pose of enhancing forming properties (fornrab:ility) and .ue;~ i.utance of damage of the resulting sheet.
The cx-olefin copolymer rubber. (B) empl.oy<xh:Lc. .i.rr the invention is an amorphous elastomeric copol.yme:r. containing w olefin as a host component, such as ethyleno-~>:ropy:l.c:ne copolymer rubber, propylene-ethylene copo:lymex- :ru1>k~c:r., ethylene-propylene non-conjugated dime copo:Lymer rubber, propylene-ethylene non-conjugated dime copolymer robber, ethylene-butadiene copolymer rubber and propy:l.ene-t>ictadiene copolymer rubber. Further, 'the cx-olefin co~ao:l.ycner .rwbber is a rubber which is reduced in flowabili.ty o:r :Lo~~~~>
flowability by the crosslinking when it i.s mixed w:it.h organic peroxide and kneaded therewith under hE:at.i.rcg . The non-conjugated diene is a generic name to dicyclopentadiene, 1,4-hexadiene, dicycloctadie;ne, methylene norbornene, ethylidene norbornene, etc.
Of these copolymer rubbers, ethylene-propylene non-~~
conjugated diene copolymer. rubber, particular:Ly et:hylene-propylene-ethylidenenorbornene copolymer rubber., i.:~
preferably used in the invention, because <v l.he:rmol>:lastic elastomer molded product excellent in heat res:i.stan<.:e, tensile characteristics and impact resilience c:an be obtained. The Mooney viscosity [MLI~n (100 °C) ] of t:he copolymer rubber is preferably in the range of 10 t:o 120, more preferably 40 to 80. In 'the case of using a copolymer rubber having Mooney viscosity of the above range, a thermoplastic elastomer product having h:i.gh t:ensi 1. c:
characteristics can be obtained. The iodine va:l.ue (degree of unsaturation) of the copolymer rubber is prc::terab:Ly not more than 16. In the thermoplastic elastomer c:onst:i.tuting the skin layer [I] of the two-layer thermop:l.ast.ic e:lastomer ,:
sheet of the invention, the po:Lyol.ef.in r.esira (A) i.~ used :in an amount of 1 to 85 parts by weight, pre:Eer-ab:l.y 20 to 80 parts by weight, more preferably 30 to 50 parts by weight, and the Oc-olefin copolymer rubber (B) is used .in an amount of 99 to 15 parts by weight, preferably 80 to 20 parts by weight, more preferably 70 to 50 parts by we:i.ght, per 100 parts by weight of 'the sum of the po:Lyolef:i.n resin (A) and the Ot-olefin copolymer rubber (B).
In the thermoplastic elastomer constituti.nd Lhe reverse surface layer [II] of the two-layer t:hermop:Lastic elastomer sheet of the invention, the polyolel::i.n re:~:i.n (A) is used in an amount of 6 to 90 parts by we:i.ght:, f:>.rc:a:erabl.y 20 to 80 parts by weight, more prefe.rabl.y 30 t.o 50 parts by weight, and the cx-olefin copolymer rubber (k3) is used in an amount of 9A to 10 parts by weight, preferably 80 to 20 parts by weight, more preferably 70 to 50 parts by weight, per 100 parts by weight of the sum of the po:Lyolet:i.n resin , (A) and the oc-olefin copolymer rubber (B) . 'Phe total amount of the polyolefin resin (A) and the cx-o:l.efin copolymer rubber (B) is 100 parts by weight. 11 dif.Eerenc~
[ (In) - (III) ] between the amount (Irs) of the cx-ol.e.Gin copolymer rubber (B) contained in the thermopl.ast:i.c elastomer of the skin layer (I) and the amo~:mt (I:fis) of the cx-olefin copolymer rubber (B) contained in the thermoplastic elastomer of the reverse surface layer (II) is in the range of 5 to 85 parts by weight, preFerab:Ly 10 to 70 parts by weight, more preferably 15 l0 50 parts by weight.
When two kinds of the thermoplastic elast:omers having a difference of the above range in the content o.t' k:tre (x-olefin copolymer rubber (B) are used, a two-:layer sheet having high vacuum forming properties and capab:l.e o:l producing a molded product especially soft in k.he touch In the invention, the thermoplastic el.asi:omer~ of the skin layer [T] and the reverse surface layer [:II]
constituting a two-layer sheet may contain a peroxi.cte non-crossl.inkable hydrocarbon gum rubber (C) and/or a mineral oil softening agent (D) in addition to the po:l.yo.lc:fin resin (A) and the oc-olefin copolymer rubber (B).
The peroxide non-crosslinkable hydrocarbon gi.rm rubber (C) employable in the invention is a gum rubber: of hydrocarbon type which is not crosslinked and is not reduced in flowability even when it is mixed with peroxide and kneaded therewith under heating. Examples of the gum rubber include pol.yisobutylene, butyl rubber (:k:l:R) , propylene-ethylene copolymer rubber having propylene content of not less than 70 o by mole, and atact:ic polypropylene. Of these, polyisobutylene and k~utyl. rubber are most preferred because of good performance and easy handling.
The peroxide non-crosslinkab:le hydroctrrbon guru :rubber (C) shows an effect to improve flowability of <:r thermoplastic elastomer composition. Tn the invent::ion, ,.
suitably employed is a peroxide non-crosslinkab.le hydrocarbon gum rubber having Mooney viscosity [ML,.~,~ (100 °C)] of not more than 60.
The peroxide non-crosslinkable hydrocarbon gum rubber (C) is used in the invention in an amount o:f 5 to _1.00 parts by weight, preferably 10 to 50 parts by weight, tTlUre preferably 15 to 40 parts by weight, per 100 parts by weight of the sum of the polyolefin resin (A) and the Cc-olefin copolymer rubber (B).
The mineral oil softening agent (D) emp:Loyable in the invention is a high-boiling petroleum cut which is generally used for mitigating intermolecular force of rubber to facilitate processing of rubber in the roll.-processing procedure, assisting di.spersibili.ty of carbon black, white carbon, etc. added as a filler, o.r reducing rigidness of vulcanized rubber to increase fl.exib:ili.ty and elasticity thereof. The mineral oil softening agent is classified into paraffin type, naphthene type, aromatic type, etc.
A molded product obtained from a thermopl.ast:i.c elastomer composition containing the naphthene type mineral oil softening agent shows less surface tackiness as compared with a molded product obtained from a thermoplastic elastomer composition containing paraffin type mineral oil softening agent, so that t:he naphthene type mineral oil softening agent is more pre:Eerab:l.y used in the invention than the paraffin type mineral. oil softening agent.
In the invention, the mineral ail soften:i.ng agent (D) is used in an amount of 5 to 100 parts by wei<jht, preferably 10 to 80 parts by weight, more preferab7.y 20 to 70 parts by weight, per 100 parts by weight. of the sum of the polyolefin resin (A) and the oc-olefin copolymer rubber (B) .
The two-layer thermoplastic elastomer sheet ol: the invention may contain other additives, provided float the addition of the additives does not mar the object of the invention. Examples of the additives include po:lyalefin plastics such as high-density polyethylene, :intermediate density polyethylene, low-density polyethylene, isotactic polypropylene and propylene-a-olefin copolymer; inorganic fillers such as calcium carbonate, calcium silicate, clay, kaolin, talc, silica, diatomaceous earth, mica powder, asbestos, alumina, barium sulfate, aluminum su:l:Eate, calcium sulfate, basic magnesium carbonate, molybdenum disulfide, graphite, glass bulb and shirasu bal._Loon; and colorants such as carbon black, titanium oxide, zinc white, blood red, ultramarine blue, Milori blue, azo pigment, nitroso pigment, lake pigment and phthalocyanine pigment.
Further, the two-layer thermoplastic el.astomer sheet of the invention there may be used known heat stab:i:Lizers such as heat stabilizers of phenol type, su:l.fi.te type, ~~~8~~~
phenylalkane type, phosphite type and amine type, ag:ing-inhibiting agent, weathering stabilizer, ant:i_staL.i.c agent, metallic soap, and lubricant such as wax. 'they can be added in such an amount as generally used for conventional polyolefin resins or oc-olefin copolymer rubbers.
If a light stabilizer such as ul.traviol.et absorl>:ing agent, light absorbing agent and hindered amin<:s is added to the thermoplastic elastomer constituting the skin :Layer [I] of the two-layer thermoplastic elastomer sheet: of the invention and a flame-retardant is added to the thermoplastic elastomer constituting the reverse surface layer [IT] thereof, there can be obtained a two-la°ryer thermoplastic elastomer sheet capable of provicLinc~ a molded product which is excellent in light resistance and flame retardance and free from occurrence of bleedout that causes marked deterioration in merchandise value.
However, if the light stabilizer and ttie .P7.amc:-retardant are together added to and allowed to present in the same thermoplastic elastomer according t:o L:he prior art, occurrence of bleedout could not be preverstecl.
There is no specific limitation on the :Li<~ht stabilizer and the flame-retardant employab:l.e a.n the;
invention, provided that they are generally used for conventional polyolefin thermoplastic elastomex~s.
Concrete examples of the light stabili.zer.s prefor~ably used in the invention include antioxidants of hindered - 1:1 -phenol type represented by pentaerythritol-tetrak:is[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] and oc:tadecy:l.-3-(3,5-di-t-butyl-~1-hydroxyphenyl)propionate; and l.i.ght stabilizers of hindered amine type represented by bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate.
In the case of using the above-mentioned l.i.ght stabilizers of hindered amine type, light stabilizers of benzotriazole type represented by 2-(3-t-butyl.-5-methyl-2-hydroxyphenyl)-5-chlorobenzotri.azole. can be employed .in combination. The antioxidants of hindered phenol type and the light stabilizers of hindered amine type uay be used singly or in combination.
The amount of the light stabilizer used i.n the invention is generally in the range of 0.07. to 0.3 phr, preferably 0.05 to 0.2 phr.
Concrete examples of the flame-retardants preferably used in the invention include inorganic flame-retarciants represented by antimony oxide and aluminum hydroxide; and halogen type flame-retardants represented by decabromodiphenyl ether and chlorinated polyethy:lene:.
The organic flame-retardant and the ha7.ogen type flame-retardant can be employed singly or :i.n comb:i.nal,ion.
When the inorganic flame-retanddnt i.s used, the amount of the flame-retardant used in the i.yvention i.:~ gene.>:ally in the range of 10 to 200 phr, preferab~.y 5 to 150 plr.
When the halogen type flame-retardant was used, the amount ~~~~28~
of the flame-retardant used is generally :in the range of 10 to 100 phr, preferably 25 to 55 ph r.
The thermoplastic elastomer as ment:i.oned above can be obtained, for example, by dynamically heat-treat:i.n<~ a blend of the above-mentioned components in the presence o.L
organic peroxide to be partially crosslinked.
The expression "dynamically heat-treat:i.ng a blend"
means that a blend is kneaded in the molten state of dissolution.
Concrete examples of organic peroxides employable for preparing the thermoplastic elastomer in the invention include dicumyl peroxide, di-tart-butylperoxi.de, 2,5-dimethyl-2,5-di-(tart-butylperoxy)hexane, 2,5-dirnethyl-2,5-di(tert-butylperoxy)hexine-3, 1,3-bis(tert-butylperoxyisopropyl)benzene, l,1-bis(tert-butylpe.roxy)-
3,3,5-trimethylcyclohexane, n-butyl-4,4-bis(tert-butylperoxy)valerate, benzoyl peroxide, p-chlorobenzoyl peroxide, 2,9-dichlorobenzoyl peroxide, tent-butylperoxybenzoate, tart-butylperbenzoate, ter:t-butylperoxyisopropyl carbonate, d:i.acetyl. peroxide, l.auroyl peroxide and tart-butylcumyl peroxide.
Of these, from the viewpoints of odor development and scorching stability, preferred are 2,5-dimethyl.-2,5-di (tart-butylperoxy) hexane, 2, 5-dimethyl-2, 5-d:i. (temt-butylperoxy)hexine-3, 1,3-bis(tert-butylperoxyisopropyl) benzene, :l, 1-bis (tart-butylper~oxy) -2~~~2~~
3,3,5-trimethylcyclohexane and n-butyl-9,9-bis(tert:--butylperoxy)valerate, and most preferred is 1,3-bis(t:ert-butylperoxyisopropyl)benzene.
The amount of the organic peroxide used a.n the invention generally is in the range of 0.05 to 3 '~ by cveight, preferably 0.1 to 1 o by weight, more preferably 0.1 to 0,5 ~ by weight, based on the total amount of the above-mentioned components (A), (B) and (C). When the amount of the organic peroxide is within the above range, the obtained thermoplastic elastomer becomes excellent in properties required for rubbers such as heat resistance, tensile characteristics, elastic recovery and :i.mpact resilience as well as excellent in strength and formability.
As the kneading apparatus, an extruder is used in the invention. Particularly, an unopened extruder is preferably used. Kneading is preferably carried out in an atmosphere of inert gas such as nitrogen or carbonic acid gas. In the invention, kneading is carried out: at such a temperature that the half-life of 'the used organic peroxide becomes shorter than 1 minute (generally at a temperature of 150 to 230 °C, preferably 170 to 290 °C), far 1 to 20 minutes, preferably 1 to 10 minutes. 'The shearing force applied in the kneading procedure is in the range of. 10 to 10~ sec-1, preferably 102 to 103 sec-1, in terms of a shear rate.
In the aforementioned partially crossli.nk:ing processing using the organic peroxide in the invention, there can be added crosslinking assistants such as sulfur, p-quinonedioxime, p,p'-dibenzoylquinonedioxime, N-methyl-N,4-dinitrosoaniline, nitrobenzene, diphenyl guanidine and trimethylolpropane-N, N'-m-phenylenedimaleimide;
polyfunctional methacrylate monomers such as divinyl.
benzene, triallyl cyanurate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, trimethylolpropane trimethacrylate and allyl methacrylate; and polyfunctional vinyl monomers such as vinyl butyrate and vinyl stearate.
By the use of these compounds, homogeneous and moderate erosslinking reaction can be expected. Of these compounds, divinyl benzene is most preferably used .in the invention, because it can be easily handled and is compatible with the Oc-olefin copolymer rubber and'the polyolefin resin which are main components of the blend to be treated. further, divinyl benzene has solvency action for the orc~ariic peroxide and serves as a dispersing assistant of the peroxide, so that a composition having homogeneous crosslinking effect and good balance between f:l.owabil:ity and physical properties can be, obtained., In the invention, the crosslinking assistant or the polyfunctional vinyl monomer is used in an amount of O.l to 2 ~ by weigtrt, preferably 0.3 to 1 ~ by weight, based on the totaa: amount of the blend to be treated. When they are used in such amount, obtainable is a composition which shows high flowability and brings about no change in physical properties caused by heating history in the molding .
procedure.
Decomposition accelerators such as tertiary am:i.nes (e.g,, triethylamine, tributylamine and 2,9,6-tris(dimethylamino)phenol) and naphthenic acid salts (e. g., aluminum, cobalt, vanadium, copper, calcium, z:ircon:ium, manganese, magnesium, lead and mercury) can be used to accelerate decomposition of the organic peroxide.
As described above, the thermoplastic elastomer is partially crosslinked when it is dynamically heat-treated in the presence of the organic peroxide.
In the invention, the expression "the thermoplastic elastomer is partially crosslinked" means that the gel content measured by the following method is not less than ~, preferably in the range of 20 to 99.5 0, morn preferably ~5 to 98 0.
20 Mt''~s.~~. -m n' of ate 1 .On _ .n 100 mg of a specimen of the thermoplastic elastomer is weighed out, and it is cut unto pieces having a size of 0.5 mm x 0.5 mm x 0.5 mm. The pieces of the specimen are immersed in 30 ml of cyclohexane at 23 °C for 48 hours in a sealed container, then the residue is taken out o:E the container onto a filter paper, and dried at: roam temperature for 72 hours until the weight of the specimen becomes constant.
From the weight of the dried .residue are subt.r~acted the total weight of the cyclohexane-insoluble components (fibrous filler, filler, pigment, etc.) other than the polymer component and the weight of the polyolefin resin component contained in the specimen before immersing in cyclohexane, and the obtained value .is "compensated final weight (Y)".
On the other hand, the weight of the cx-olefin copolymer rubber contained in the specimen, namely, the value obtained by subtracting the weight of the cyclohexane-soluble component l (e.g., mineral. oil and plasticizer) other than the Oc.-olefin copolymer rubber, the weight of the polyolefin resin component 2 and the weight of the cyclohexane-insoluble component 3 (e. g., fibrous filler, filler and pigment) other than the polymer component from the weight of the specimen, is "compensated initial weight (X)".
The gel content is determined by the following formula:
Compensated final weight (Y) Gel content (wt.~) _ x 100 Compensated initial weigtxt (X) In the present invention, the light stabilizers and the flame-retardants are added at any steps, constituting the process for producing the thermoplastic elastomer composition. FIowever, it is preferred that the flame-s retardant is added to the thermoplastic elastomer by using an extruder or Banbury mixer intermediately or with an elapse of time after the dynamically heat-treatment in the presence of the organic peroxide.
In the invention, the skin layer [I] composed of the thermoplastic elastomer constitutes a skin layer of a vacuum forming molded product. The thickness of the skin layer [I] constituting a skin layer of the vacuum Forming molded product is generally in the range of 0.01 to 50 mm, preferably 0.10 to 20 mm, while the thickness of the other layer [II] constituting the inner layer of the vacuum forming molded product is generally in the range of 0.01 to 100 mm, preferably 0.10 to 50 mm.
The two-layer thermoplastic elastomer sheet of the invention can be obtained by fusing the above-mentioned two kinds of the thermoplastic elastomers to each other utilizing, for example, conventionally known extrusion laminating method or injection molding method.
Otherwise, the two-layer thermoplastic el.astomer sheet of the invention can be also obtained by fusing two kinds of sheets having been beforehand molded, which constitutes the skin layer [I] and the reverse surface layer [:LI] of the two-layer sheet, at a temperature not lower than the temperature at which at least one of the two sheets is melted using a calender roll molding machine, a compression molding machine, etc.
Further, the two-layer thermoplastic el.astomer sheet of the invention can be also obtained by fusing a beforehand molded sheet which constitutes the skin layer [I] or the reverse surface layer [II] of the two-~.ayer sheet to a sheet which constitutes the reverse surface layer [IT] or the skin layer [I] of the two-layer sheet at the time when the latter sheet is prepared by extrusion molding or calendering.
The two-layer thermoplastic elastomer sheet of the invention is generally subjected to vacuum forming with other core materials to produce a molded product being particularly soft in the touch.
.F~F ~.r~.T OF THE IN~NTTON
The two-layer thermoplastic elastomer sheet of the invention is excellent in yaculm forming properties and can provide a molded product excellent in the soft touch.
Further, the two-layer thermoplastic elastomer sheet of the invention also shows softness, flexibility and warmth in its appearance.
The two-layer thermoplastic elastomer sheet of the invention having the above-mentioned effects can be widely employed for various interior automotive trim such as instrument panel.
The present invention is further described by the fol-lowing examples, but the examples are given by no means to restrict the invention.
At first, methods for evaluating vacuum forming properties (formability) and the soft: touch of two-Layer thermoplastic elastomer sheets obtained by an example and comparative examples and single-layer sheets produced using the components of the two-Layer sheets are described below.
[Evaluation Method]
(1) Evaluation on vacuum forming properties (formability) The sheet is subjected to vacuum forming using a drape forming mold until the extensibility of the sheet becomes 250 ~ and 900 ~, and then occurrence of sheet break is observed.
Condition of drape forming: upper and lower heaters are operated so that the surface temperature of the sheet is 150 °C.
(2) Evaluation on the soft touch The surface of the vacuum forming molded product is touched with fingers, and the touch is classified in o 5 levels.
5: very soft 9: soft 3: normal 2: hard 1: very hard $KAMPT.~ 1 In -the first place, pellets of two kinds of thermoplastic elastomers (referred to hereinafter as TPE
(I) and TPE (II)) were prepared as follows.
[Preparation of pellet of TPE (I)]
37 parts by weight of a isotactic polypropylene resin (i) [melt flaw rate: 13 g/10 min (230 °C)], 63 parts by weight of an ethylene-propylene-ethylidenenorbornene terpolymer rubber (ii) [ethylene unit / propylene unit (molar ratio): 78/22, iodine value: 15, Mooney viscosity ML1+q (121 °C): 61], and 30 parts by weight of a naphthene type process oil (iii.) were kneaded at 180 °C for 5 minutes in a nitrogen atmosphere using Banbury mixer . Than, the obtained kneadate was cut into angular pellets a sing a sheet cutter.
Thereafter, with 100 parts by weight of the angular pellets was kneaded 1 part by weight of a mixture (iv) of 20 wt.$ of 1,3-bis(tert-butylperoxyisopropyl)benzene ,-30 wt.~ of divinyl benzene and 50 wt.o of a parafFin mineral oil in Henschel mixer. Then, the obtained kneadate was extruded at 220 °C in a nitrogen atmosphere using an extruder, to prepare pellets of a thermoplastic elastomer [TPE (1) ] .
[Preparation of pellet of TPE (II)]
The above procedure for preparing the pellets of TPE
(I) was repeated except for using the isotactic polypropylene resin (i) in an amount of 50 parts by weight and the ethylene-propylene-ethylidenenorbornene terpolymer rubber (ii) in an amount of 50 parts by weight, to prepare pellets of a thermoplastic elastomer [TPE (II)].
Then, a skin layer sheet of a two-layer sheet was prepared from the above pellets of TPE (I) in the following manner.
[Preparation of TPE (I) sheet]
The pellets of TPE (I) were melted at 220 °C and subjected to calendering using a calendering molding machine (produced by NIPPON Roll, Co., Ltd.), to obtain a thermoplastic elastomer [TPE (I)] sheet having a thickness of 0,3 mm.
[Preparation of two-layer sheet]
The pellets of TPE (II).were melted at 220 °C, and the., obtained molten TPE (II) was coated on the reverse surface of the above TPE (I) sheet using a calender:ing molding machine (produced by NIPPON Roll, Co., Ltd.), to obtain a two-layer thermoplastic elastomer sheet having a thickness of 0.9 mm.
The obtained two-layer thermoplastic elastomer sheet was evaluated on the vacuum forming properties and the soft touch according to the aforementioned evaluation methods.
The results are set forth in Table 1.
.~OM~3Am_rVE EXAMPr_,E 1 A thermoplastic elastomer [TPE (T)] sheet having a thickness of 9 mm was prepared in the same manner as that for preparing the TPE (T) sheet in Example 1.
Thus prepared sheet was evaluated on the vacuum forming properties and softness according to the aforementioned evaluation methods.
The results are set forth in Table 1.
~,OMPARATTVE EXAM T~ .
The procedure for preparing the TPE (:I) sheet in Example 1 was repeated except that pellets of TPE (TI) was used instead of the pellets of TPE (I), to prepare a thermoplastic elastomer [TPE (II)] sheet having a thickness of 0.9 mm.
Thus prepared sheet was evaluated on the vacuzum forming properties and softness according to the aforementioned evaluation methods.
The results are set forth in Table 1.
~OMPARATTVE EXAMP~~
[Preparation of pellet of TPE (III)]
'Phe procedure for preparing the pellets of TPE (I) in Example 1 was repeated except for using the isotactic polypropylene resin (i) in an amount of 10 parts by weight and the ethylene-propylene-ethylidenenorbornene terpolymer rubber (ii) in an amount of 90 parts by weight, to prepare pellets of a thermoplastic elastomer [TPE (III)].
[Preparation of pellet of TPE (IV)]
The procedure for preparing the pellets of TPE (I) in Example 1 was repeated except far using the isotac is polypropylene resin (i) in an amount of 97 parts by weight and the ethylene-propylene-ethylidenenorbornene terpolymer rubber (ii) in an amount of 3 parts by we9.ght, to prepare pellets of a thermoplastic elastomer [TPE (IV)].
Then, a skin layer sheet of a two-layer sheet was prepared from the above pellets of TPE (III) in the Following manner.
[Preparation of TPE (III) sheet]
The pellets of TPE (III) were melted at 220 °C and subjected to calendering using a calendering molding machine (produced by NIPPON Roll, Co., Ltd.), to obtain a thermoplastic elastomer [TPE (III)] sheet having a thickness of 0.3 mm.
[Preparation of two-layer sheet) The pellets of TPE (IV) were melted at 220 °C, and the.., obtained molten TPE (IV) was coated on the reverse surface of the above TPE (IIT) sheet using a calendering molding machine (produced by NTPPON Roll, Co., Ltd.), to obtain a two-layer thermoplastic elastomer sheet having a thickness of 0.9 mm.
The obtained two-layer thermoplastic elastomer sheet was evaluated on the vacuum forming properties and the soft touch according to the aforementioned evaluation methods.
The results are set forth in Table d.
[Preparation of pellet of TPE (V)) The procedure for preparing the pellets of TPE (I) in Example 1 was repeated except for using the isotactic polypropylene resin (i) in an amount of 40 parts by weight and the ethylene-propylene-ethylidenenorbornene terpolymer rubber (ii) in an amount of 60 parts by weight, to prepare pellets of a thermoplastic elastome.r [TPE (V)).
[Preparation of two-layer sheet]
The pellets of TPE (V) were melted at 220 °C, and the obtained molten TPE (V) was coated on the reverse surface of the TPE (T) sheet of Example 1 using a calendering molding machine (produced by NIPPON Roll, Co., Ltd.), to obtain a two-layer thermoplastic elastomer sheet having a thickness of 0.9 mm.
The obtained two-layer thermoplastic elastomer sheet was evaluated on the vacuum forming properties and softness according 'to the aforementioned evaluation methods.
The results are set forth in Table 1.
Table 1 Ex. 1 Com. Ex. Com. Com. Ex. Com.
1 Ex. 3 Ex.
Structureskin single single skin layerskin layer layer of vacuumof layer layer of of of of forming TPE (I),TPE (I) TPE (II)TPE (III),TPE (I), molded reverse reverse reverse product surface surface surface layer layer layer of of of TPE (II) TPE (IV) TPE (V) Difference of rubber content 13 - - 87 3 [part by wei ht) Vacuum forming properties Exterisi-break break break break break is not is not is not iS is not bility observedobserved observedobserved observed of 250 ~
Extensi- break break break break break is not is is not is is bility observedobserved observedobserved observed of 400 $
Softness Extensi-bility 5 5 3 5 5 of 250 $ .. .
Extensi-bility 5 5 3 5 5 of 400 $
Note: Difference of rubber content in Table 1 is obtained by the formula of [(rubbe.r content of skin layer) - (rubber content of reverse surface laver)1.
Of these, from the viewpoints of odor development and scorching stability, preferred are 2,5-dimethyl.-2,5-di (tart-butylperoxy) hexane, 2, 5-dimethyl-2, 5-d:i. (temt-butylperoxy)hexine-3, 1,3-bis(tert-butylperoxyisopropyl) benzene, :l, 1-bis (tart-butylper~oxy) -2~~~2~~
3,3,5-trimethylcyclohexane and n-butyl-9,9-bis(tert:--butylperoxy)valerate, and most preferred is 1,3-bis(t:ert-butylperoxyisopropyl)benzene.
The amount of the organic peroxide used a.n the invention generally is in the range of 0.05 to 3 '~ by cveight, preferably 0.1 to 1 o by weight, more preferably 0.1 to 0,5 ~ by weight, based on the total amount of the above-mentioned components (A), (B) and (C). When the amount of the organic peroxide is within the above range, the obtained thermoplastic elastomer becomes excellent in properties required for rubbers such as heat resistance, tensile characteristics, elastic recovery and :i.mpact resilience as well as excellent in strength and formability.
As the kneading apparatus, an extruder is used in the invention. Particularly, an unopened extruder is preferably used. Kneading is preferably carried out in an atmosphere of inert gas such as nitrogen or carbonic acid gas. In the invention, kneading is carried out: at such a temperature that the half-life of 'the used organic peroxide becomes shorter than 1 minute (generally at a temperature of 150 to 230 °C, preferably 170 to 290 °C), far 1 to 20 minutes, preferably 1 to 10 minutes. 'The shearing force applied in the kneading procedure is in the range of. 10 to 10~ sec-1, preferably 102 to 103 sec-1, in terms of a shear rate.
In the aforementioned partially crossli.nk:ing processing using the organic peroxide in the invention, there can be added crosslinking assistants such as sulfur, p-quinonedioxime, p,p'-dibenzoylquinonedioxime, N-methyl-N,4-dinitrosoaniline, nitrobenzene, diphenyl guanidine and trimethylolpropane-N, N'-m-phenylenedimaleimide;
polyfunctional methacrylate monomers such as divinyl.
benzene, triallyl cyanurate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, trimethylolpropane trimethacrylate and allyl methacrylate; and polyfunctional vinyl monomers such as vinyl butyrate and vinyl stearate.
By the use of these compounds, homogeneous and moderate erosslinking reaction can be expected. Of these compounds, divinyl benzene is most preferably used .in the invention, because it can be easily handled and is compatible with the Oc-olefin copolymer rubber and'the polyolefin resin which are main components of the blend to be treated. further, divinyl benzene has solvency action for the orc~ariic peroxide and serves as a dispersing assistant of the peroxide, so that a composition having homogeneous crosslinking effect and good balance between f:l.owabil:ity and physical properties can be, obtained., In the invention, the crosslinking assistant or the polyfunctional vinyl monomer is used in an amount of O.l to 2 ~ by weigtrt, preferably 0.3 to 1 ~ by weight, based on the totaa: amount of the blend to be treated. When they are used in such amount, obtainable is a composition which shows high flowability and brings about no change in physical properties caused by heating history in the molding .
procedure.
Decomposition accelerators such as tertiary am:i.nes (e.g,, triethylamine, tributylamine and 2,9,6-tris(dimethylamino)phenol) and naphthenic acid salts (e. g., aluminum, cobalt, vanadium, copper, calcium, z:ircon:ium, manganese, magnesium, lead and mercury) can be used to accelerate decomposition of the organic peroxide.
As described above, the thermoplastic elastomer is partially crosslinked when it is dynamically heat-treated in the presence of the organic peroxide.
In the invention, the expression "the thermoplastic elastomer is partially crosslinked" means that the gel content measured by the following method is not less than ~, preferably in the range of 20 to 99.5 0, morn preferably ~5 to 98 0.
20 Mt''~s.~~. -m n' of ate 1 .On _ .n 100 mg of a specimen of the thermoplastic elastomer is weighed out, and it is cut unto pieces having a size of 0.5 mm x 0.5 mm x 0.5 mm. The pieces of the specimen are immersed in 30 ml of cyclohexane at 23 °C for 48 hours in a sealed container, then the residue is taken out o:E the container onto a filter paper, and dried at: roam temperature for 72 hours until the weight of the specimen becomes constant.
From the weight of the dried .residue are subt.r~acted the total weight of the cyclohexane-insoluble components (fibrous filler, filler, pigment, etc.) other than the polymer component and the weight of the polyolefin resin component contained in the specimen before immersing in cyclohexane, and the obtained value .is "compensated final weight (Y)".
On the other hand, the weight of the cx-olefin copolymer rubber contained in the specimen, namely, the value obtained by subtracting the weight of the cyclohexane-soluble component l (e.g., mineral. oil and plasticizer) other than the Oc.-olefin copolymer rubber, the weight of the polyolefin resin component 2 and the weight of the cyclohexane-insoluble component 3 (e. g., fibrous filler, filler and pigment) other than the polymer component from the weight of the specimen, is "compensated initial weight (X)".
The gel content is determined by the following formula:
Compensated final weight (Y) Gel content (wt.~) _ x 100 Compensated initial weigtxt (X) In the present invention, the light stabilizers and the flame-retardants are added at any steps, constituting the process for producing the thermoplastic elastomer composition. FIowever, it is preferred that the flame-s retardant is added to the thermoplastic elastomer by using an extruder or Banbury mixer intermediately or with an elapse of time after the dynamically heat-treatment in the presence of the organic peroxide.
In the invention, the skin layer [I] composed of the thermoplastic elastomer constitutes a skin layer of a vacuum forming molded product. The thickness of the skin layer [I] constituting a skin layer of the vacuum Forming molded product is generally in the range of 0.01 to 50 mm, preferably 0.10 to 20 mm, while the thickness of the other layer [II] constituting the inner layer of the vacuum forming molded product is generally in the range of 0.01 to 100 mm, preferably 0.10 to 50 mm.
The two-layer thermoplastic elastomer sheet of the invention can be obtained by fusing the above-mentioned two kinds of the thermoplastic elastomers to each other utilizing, for example, conventionally known extrusion laminating method or injection molding method.
Otherwise, the two-layer thermoplastic el.astomer sheet of the invention can be also obtained by fusing two kinds of sheets having been beforehand molded, which constitutes the skin layer [I] and the reverse surface layer [:LI] of the two-layer sheet, at a temperature not lower than the temperature at which at least one of the two sheets is melted using a calender roll molding machine, a compression molding machine, etc.
Further, the two-layer thermoplastic el.astomer sheet of the invention can be also obtained by fusing a beforehand molded sheet which constitutes the skin layer [I] or the reverse surface layer [II] of the two-~.ayer sheet to a sheet which constitutes the reverse surface layer [IT] or the skin layer [I] of the two-layer sheet at the time when the latter sheet is prepared by extrusion molding or calendering.
The two-layer thermoplastic elastomer sheet of the invention is generally subjected to vacuum forming with other core materials to produce a molded product being particularly soft in the touch.
.F~F ~.r~.T OF THE IN~NTTON
The two-layer thermoplastic elastomer sheet of the invention is excellent in yaculm forming properties and can provide a molded product excellent in the soft touch.
Further, the two-layer thermoplastic elastomer sheet of the invention also shows softness, flexibility and warmth in its appearance.
The two-layer thermoplastic elastomer sheet of the invention having the above-mentioned effects can be widely employed for various interior automotive trim such as instrument panel.
The present invention is further described by the fol-lowing examples, but the examples are given by no means to restrict the invention.
At first, methods for evaluating vacuum forming properties (formability) and the soft: touch of two-Layer thermoplastic elastomer sheets obtained by an example and comparative examples and single-layer sheets produced using the components of the two-Layer sheets are described below.
[Evaluation Method]
(1) Evaluation on vacuum forming properties (formability) The sheet is subjected to vacuum forming using a drape forming mold until the extensibility of the sheet becomes 250 ~ and 900 ~, and then occurrence of sheet break is observed.
Condition of drape forming: upper and lower heaters are operated so that the surface temperature of the sheet is 150 °C.
(2) Evaluation on the soft touch The surface of the vacuum forming molded product is touched with fingers, and the touch is classified in o 5 levels.
5: very soft 9: soft 3: normal 2: hard 1: very hard $KAMPT.~ 1 In -the first place, pellets of two kinds of thermoplastic elastomers (referred to hereinafter as TPE
(I) and TPE (II)) were prepared as follows.
[Preparation of pellet of TPE (I)]
37 parts by weight of a isotactic polypropylene resin (i) [melt flaw rate: 13 g/10 min (230 °C)], 63 parts by weight of an ethylene-propylene-ethylidenenorbornene terpolymer rubber (ii) [ethylene unit / propylene unit (molar ratio): 78/22, iodine value: 15, Mooney viscosity ML1+q (121 °C): 61], and 30 parts by weight of a naphthene type process oil (iii.) were kneaded at 180 °C for 5 minutes in a nitrogen atmosphere using Banbury mixer . Than, the obtained kneadate was cut into angular pellets a sing a sheet cutter.
Thereafter, with 100 parts by weight of the angular pellets was kneaded 1 part by weight of a mixture (iv) of 20 wt.$ of 1,3-bis(tert-butylperoxyisopropyl)benzene ,-30 wt.~ of divinyl benzene and 50 wt.o of a parafFin mineral oil in Henschel mixer. Then, the obtained kneadate was extruded at 220 °C in a nitrogen atmosphere using an extruder, to prepare pellets of a thermoplastic elastomer [TPE (1) ] .
[Preparation of pellet of TPE (II)]
The above procedure for preparing the pellets of TPE
(I) was repeated except for using the isotactic polypropylene resin (i) in an amount of 50 parts by weight and the ethylene-propylene-ethylidenenorbornene terpolymer rubber (ii) in an amount of 50 parts by weight, to prepare pellets of a thermoplastic elastomer [TPE (II)].
Then, a skin layer sheet of a two-layer sheet was prepared from the above pellets of TPE (I) in the following manner.
[Preparation of TPE (I) sheet]
The pellets of TPE (I) were melted at 220 °C and subjected to calendering using a calendering molding machine (produced by NIPPON Roll, Co., Ltd.), to obtain a thermoplastic elastomer [TPE (I)] sheet having a thickness of 0,3 mm.
[Preparation of two-layer sheet]
The pellets of TPE (II).were melted at 220 °C, and the., obtained molten TPE (II) was coated on the reverse surface of the above TPE (I) sheet using a calender:ing molding machine (produced by NIPPON Roll, Co., Ltd.), to obtain a two-layer thermoplastic elastomer sheet having a thickness of 0.9 mm.
The obtained two-layer thermoplastic elastomer sheet was evaluated on the vacuum forming properties and the soft touch according to the aforementioned evaluation methods.
The results are set forth in Table 1.
.~OM~3Am_rVE EXAMPr_,E 1 A thermoplastic elastomer [TPE (T)] sheet having a thickness of 9 mm was prepared in the same manner as that for preparing the TPE (T) sheet in Example 1.
Thus prepared sheet was evaluated on the vacuum forming properties and softness according to the aforementioned evaluation methods.
The results are set forth in Table 1.
~,OMPARATTVE EXAM T~ .
The procedure for preparing the TPE (:I) sheet in Example 1 was repeated except that pellets of TPE (TI) was used instead of the pellets of TPE (I), to prepare a thermoplastic elastomer [TPE (II)] sheet having a thickness of 0.9 mm.
Thus prepared sheet was evaluated on the vacuzum forming properties and softness according to the aforementioned evaluation methods.
The results are set forth in Table 1.
~OMPARATTVE EXAMP~~
[Preparation of pellet of TPE (III)]
'Phe procedure for preparing the pellets of TPE (I) in Example 1 was repeated except for using the isotactic polypropylene resin (i) in an amount of 10 parts by weight and the ethylene-propylene-ethylidenenorbornene terpolymer rubber (ii) in an amount of 90 parts by weight, to prepare pellets of a thermoplastic elastomer [TPE (III)].
[Preparation of pellet of TPE (IV)]
The procedure for preparing the pellets of TPE (I) in Example 1 was repeated except far using the isotac is polypropylene resin (i) in an amount of 97 parts by weight and the ethylene-propylene-ethylidenenorbornene terpolymer rubber (ii) in an amount of 3 parts by we9.ght, to prepare pellets of a thermoplastic elastomer [TPE (IV)].
Then, a skin layer sheet of a two-layer sheet was prepared from the above pellets of TPE (III) in the Following manner.
[Preparation of TPE (III) sheet]
The pellets of TPE (III) were melted at 220 °C and subjected to calendering using a calendering molding machine (produced by NIPPON Roll, Co., Ltd.), to obtain a thermoplastic elastomer [TPE (III)] sheet having a thickness of 0.3 mm.
[Preparation of two-layer sheet) The pellets of TPE (IV) were melted at 220 °C, and the.., obtained molten TPE (IV) was coated on the reverse surface of the above TPE (IIT) sheet using a calendering molding machine (produced by NTPPON Roll, Co., Ltd.), to obtain a two-layer thermoplastic elastomer sheet having a thickness of 0.9 mm.
The obtained two-layer thermoplastic elastomer sheet was evaluated on the vacuum forming properties and the soft touch according to the aforementioned evaluation methods.
The results are set forth in Table d.
[Preparation of pellet of TPE (V)) The procedure for preparing the pellets of TPE (I) in Example 1 was repeated except for using the isotactic polypropylene resin (i) in an amount of 40 parts by weight and the ethylene-propylene-ethylidenenorbornene terpolymer rubber (ii) in an amount of 60 parts by weight, to prepare pellets of a thermoplastic elastome.r [TPE (V)).
[Preparation of two-layer sheet]
The pellets of TPE (V) were melted at 220 °C, and the obtained molten TPE (V) was coated on the reverse surface of the TPE (T) sheet of Example 1 using a calendering molding machine (produced by NIPPON Roll, Co., Ltd.), to obtain a two-layer thermoplastic elastomer sheet having a thickness of 0.9 mm.
The obtained two-layer thermoplastic elastomer sheet was evaluated on the vacuum forming properties and softness according 'to the aforementioned evaluation methods.
The results are set forth in Table 1.
Table 1 Ex. 1 Com. Ex. Com. Com. Ex. Com.
1 Ex. 3 Ex.
Structureskin single single skin layerskin layer layer of vacuumof layer layer of of of of forming TPE (I),TPE (I) TPE (II)TPE (III),TPE (I), molded reverse reverse reverse product surface surface surface layer layer layer of of of TPE (II) TPE (IV) TPE (V) Difference of rubber content 13 - - 87 3 [part by wei ht) Vacuum forming properties Exterisi-break break break break break is not is not is not iS is not bility observedobserved observedobserved observed of 250 ~
Extensi- break break break break break is not is is not is is bility observedobserved observedobserved observed of 400 $
Softness Extensi-bility 5 5 3 5 5 of 250 $ .. .
Extensi-bility 5 5 3 5 5 of 400 $
Note: Difference of rubber content in Table 1 is obtained by the formula of [(rubbe.r content of skin layer) - (rubber content of reverse surface laver)1.
Claims (10)
1. A two-layer thermoplastic elastomer sheet comprising a skin layer [I] and a reverse surface layer [II], wherein:
said skin layer is composed of a thermoplastic elastomer containing a polyolefin resin (A) in an amount of 1 to 85 parts by weight and an .alpha.-olefin copolymer rubber (B) in an amount of 99 to 15 parts by weight, total amount of (A) and (B) being 100 parts by weight;
said reverse surface layer [II] is composed of a thermoplastic elastomer containing a polyolefin resin (A) in an amount of 6 to 90 parts by weight and an .alpha.-olefin copolymer rubber (B) in an amount of 94 to 10 parts by weight, total amount of (A) and (B) being 100 parts by weight; and a difference [(I B) - (II B)] between the amount (I B) of the .alpha.-olefin copolymer rubber (B) contained in the thermoplastic elastomer of the skin layer (I) and the amount (II B) of the .alpha.-olefin copolymer rubber (B) contained in the thermoplastic elastomer of the reverse surface layer (II) is in the range of 5 to 85 parts by weight.
said skin layer is composed of a thermoplastic elastomer containing a polyolefin resin (A) in an amount of 1 to 85 parts by weight and an .alpha.-olefin copolymer rubber (B) in an amount of 99 to 15 parts by weight, total amount of (A) and (B) being 100 parts by weight;
said reverse surface layer [II] is composed of a thermoplastic elastomer containing a polyolefin resin (A) in an amount of 6 to 90 parts by weight and an .alpha.-olefin copolymer rubber (B) in an amount of 94 to 10 parts by weight, total amount of (A) and (B) being 100 parts by weight; and a difference [(I B) - (II B)] between the amount (I B) of the .alpha.-olefin copolymer rubber (B) contained in the thermoplastic elastomer of the skin layer (I) and the amount (II B) of the .alpha.-olefin copolymer rubber (B) contained in the thermoplastic elastomer of the reverse surface layer (II) is in the range of 5 to 85 parts by weight.
2. The two-layer thermoplastic elastomer sheet as claimed in claim 1, wherein the thermoplastic elastomer constituting the skin layer [I] contains a peroxide non-crosslinkable hydrocarbon gum rubber (C) and/or a mineral oil softening agent (D).
3. The two-layer thermoplastic elastomer sheet as claimed in claim 1 or claim 2, wherein the thermoplastic elastomer constituting the reverse surface layer [II]
contains a peroxide non-crosslinkable hydrocarbon gum rubber (C) and/or a mineral oil softening agent (D).
contains a peroxide non-crosslinkable hydrocarbon gum rubber (C) and/or a mineral oil softening agent (D).
9. The two-layer thermoplastic elastomer sheet as claimed in any of claim 1 to claim 3, wherein the thermoplastic elastomer constituting the skin layer [I]
contains a light stabilizer and the thermoplastic elastomer constituting the reverse surface layer [II] contains a flame-retardant.
contains a light stabilizer and the thermoplastic elastomer constituting the reverse surface layer [II] contains a flame-retardant.
5. The two layer thermoplastic elastomer sheet as claimed in claim 1 or 2, wherein:
the polyolefin resin (A) is a homopolymer of ethylene or propylene or is a copolymer of ethylene/propylene or of a major amount of ethylene or propylene and a small amount of another polymerizable monomer selected from the group consisting of 1-butane, 1-hexane, 4-methyl-1-pentane, vinyl acetate, ethyl acrylate and methacrylic acid and the polyolefin resin (A) has a melt index (ASTM-D 1238-65T at 230 °C) of 0.1 to 100;
the .alpha.-olefin copolymer rubber (B) is an amorphous elastomeric copolymer containing an .alpha.-olefin as a host component and being selected from the group consisting of ethylene/propylene copolymer rubber, propylene/ethylene copolymer rubber, ethylene/propylene/non-conjugated diene copolymer rubber, propylene/ethylene/non-conjugated diene copolymer rubber, ethylene/butadiene copolymer rubber and propylene/butadiene copolymer rubbers the .alpha.-olefin copolymer rubber (B) has been partially crosslinked by kneading the rubber under heat in a molten state in the presence of an organic peroxide to reduce its flowability; and the .alpha.-olefin copolymer rubber (B) has a Mooney viscosity [ML1+4 (100°C)] of 10 to 120 before being subjected to the kneading under heat.
the polyolefin resin (A) is a homopolymer of ethylene or propylene or is a copolymer of ethylene/propylene or of a major amount of ethylene or propylene and a small amount of another polymerizable monomer selected from the group consisting of 1-butane, 1-hexane, 4-methyl-1-pentane, vinyl acetate, ethyl acrylate and methacrylic acid and the polyolefin resin (A) has a melt index (ASTM-D 1238-65T at 230 °C) of 0.1 to 100;
the .alpha.-olefin copolymer rubber (B) is an amorphous elastomeric copolymer containing an .alpha.-olefin as a host component and being selected from the group consisting of ethylene/propylene copolymer rubber, propylene/ethylene copolymer rubber, ethylene/propylene/non-conjugated diene copolymer rubber, propylene/ethylene/non-conjugated diene copolymer rubber, ethylene/butadiene copolymer rubber and propylene/butadiene copolymer rubbers the .alpha.-olefin copolymer rubber (B) has been partially crosslinked by kneading the rubber under heat in a molten state in the presence of an organic peroxide to reduce its flowability; and the .alpha.-olefin copolymer rubber (B) has a Mooney viscosity [ML1+4 (100°C)] of 10 to 120 before being subjected to the kneading under heat.
6. The two layer thermoplastic elastomer sheet as claimed in claim 5, wherein the polyolefin resin (A) is polypropylene resin having a melt index (ASTM-D 1238-65T at 230°C) of 5 to 50.
7. The two layer thermoplastic elastomer sheet as claimed in claim 5 or 6, wherein the .alpha.-olefin copolymer rubber (B) is ethylene/propylene/non-conjugated diene copolymer rubber having a Mooney viscosity [ML1+4 (100°C)] of 10 to 80 before being subjected to the kneading under heat.
8. The two layer thermoplastic elastomer sheet as claimed in any one of claims 1 to 4, wherein at least one of the thermoplastic elastomers of the skin layer and the reverse surface layer is partially crosslinked.
9. The two layer thermoplastic elastomer sheet as claimed in claim 8, wherein only the thermoplastic elastomer of the skin layer is partially crosslinked.
10. The two layer thermoplastic elastomer sheet as claimed in claim 8, wherein the thermoplastic elastomers of both the skin and reverse surface layers are partially crosslinked.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP40488390 | 1990-12-21 | ||
| JP404883/1990 | 1990-12-21 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2058285A1 CA2058285A1 (en) | 1992-06-22 |
| CA2058285C true CA2058285C (en) | 2002-02-05 |
Family
ID=18514539
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002058285A Expired - Fee Related CA2058285C (en) | 1990-12-21 | 1991-12-20 | Two-layer thermoplastic elastomer sheet |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JP2967957B2 (en) |
| KR (1) | KR950004151B1 (en) |
| CA (1) | CA2058285C (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4860853B2 (en) * | 2001-09-28 | 2012-01-25 | 出光ユニテック株式会社 | Multilayer film and surface protective film |
| JP4841955B2 (en) * | 2003-12-05 | 2011-12-21 | 三井化学株式会社 | Olefin-based thermoplastic elastomer laminate |
| EP3438184A1 (en) * | 2017-08-03 | 2019-02-06 | Sika Technology Ag | Polymer composition with improved mechanical properties |
-
1991
- 1991-12-03 JP JP3319373A patent/JP2967957B2/en not_active Expired - Fee Related
- 1991-12-20 CA CA002058285A patent/CA2058285C/en not_active Expired - Fee Related
- 1991-12-21 KR KR1019910023746A patent/KR950004151B1/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| KR920011716A (en) | 1992-07-24 |
| JP2967957B2 (en) | 1999-10-25 |
| KR950004151B1 (en) | 1995-04-27 |
| JPH0538786A (en) | 1993-02-19 |
| CA2058285A1 (en) | 1992-06-22 |
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