JPS60173032A - Thermoplastic elastomer composition good in injection weldability and gloss - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention The present invention mainly consists of an ethylene-α-olefin amorphous copolymer (α) and a propylene-α-olefin crystalline copolymer (b) having 4 or more carbon atoms, The present invention relates to a thermoplastic elastomer composition with good injection fusion properties and gloss, characterized in that both of these components are partially crosslinked through propylene chains, and a method for producing the same.

Olefinic thermoplastic elastomers exhibit elastomer properties similar to those of vulcanized rubber, while exhibiting moldability equivalent to thermoplastic resins such as polyethylene and polypropylene. Utilizing this fact, they are molded in the same way as ordinary resins, and molded products are It has begun to be used primarily for applications that require elastomer properties, such as automobile bumpers, exterior moldings, windshield gaskets, emblems and interior skin sheets, and gaskets for building materials.

Among the above applications, olefinic thermoplastic elastomers to be used in fields such as automobile windshield gaskets and various gaskets for building materials, which require properties similar to those of vulcanized rubber, are among ordinary olefinic thermoplastic elastomers. It is obtained by increasing the content of the ethylene-α-olefin copolymer elastomer component.

However, the flexible thermoplastic elastomer obtained in this way has poor fluidity when melted.1. It is difficult to directly mold molded products such as automobile wind seal gaskets and building material gaskets, which require large and complex shapes, by injection molding.

On the other hand, since this soft thermoplastic elastomer has good shapeability, it is conceivable to use this property to mold the above article by extrusion molding, but in this case, it is possible to mold the above-mentioned article by extrusion molding. It is necessary to join the ends of each other.

To perform this joining, two or more extruded products to be joined are placed in a split mold.1-1 A thermoplastic elastomer with good fusion properties is injected between the ends of both molded products to bond them together. It is preferable to fuse. In this case, it is preferable that the split mold has a structure to which injection molding can be applied.

However, in many cases, even if extrusion molded products of thermoplastic elastomer are joined by the above method, it is difficult to perform the joining with a strength that can be used for practical purposes.

As a measure to solve this problem, the present applicant has already applied for a method for improving the joint strength by preheating the ends of the extruded products to be joined in a split mold (Japanese Patent Application No.
No. 5670).

As a result of extensive research into a method for injection fusing the ends of thermoplastic elastomer extrusion products without preheating as described above, the present inventors prepared the following composition in a split mold. The present invention has been completed based on the discovery that a molded article joined with a strength suitable for practical use can be obtained by inserting the extruded molded article between the ends of two or more thermoplastic elastomer extrusion molded articles.

The radically decomposable crystalline polyolefin (c) which may be used together with the component (α) of the composition of the present invention is usually a homopolymer, copolymer or a mixture thereof of an α-olefin having 6 or more carbon atoms. The degree of crystallinity measured by X-ray diffraction is usually 40% or more, preferably 50% or more. Copolymerized unit and 1. However, the bone usually contains less than 40 mole of ethylene.
Preferably it is 20 molti or less.

The copolymer can be produced by either a block polymerization method or a random polymerization method, but since it is necessary to achieve the above-mentioned lower limit of crystallinity, in the random copolymerization method, copolymerization of fewer copolymer units is performed. The content in the coalesce is 15
molti or less, preferably 10 molti or less, and in the block copolymerization method, the content of the small five-sided copolymerized unit in the copolymer is usually 40 molti or less, preferably 2 molti or less.
Set to 0 molti or less.

Among them, polypropylene having a crystallinity of 50 inches or more is preferred.

The ethylene-α-olefin amorphous copolymer which is the component (α) of the present invention is a binary copolymer of ethylene and α-olefin, or a non-conjugated diene as a third component, for example, a binary copolymer of ethylene and an α-olefin. .Aliphatic dienes such as 4-hexadiene, dicyclopentadiene, 5-ethylidene norbornene, 5
- A terpolymer containing an alicyclic diene such as methylenenorbornene or 5-vinylnorbornene, which has a crystallinity of usually 65% or less, preferably 20% or less, as measured by X-ray diffraction. say.

The ethylene unit content of the binary copolymer is usually 30 to 95 moles, preferably 50 to 85 moles, the remainder being α-olefin, and the melt flow rate (190tZ') is usually 0.1 to 120 f/10mm. Preferably 0.1~
20f/10m, melt flow rate <230C) is usually 0.1 to 20Of/10m, preferably 0.1 to 5(
In order of 1/10, the iodine value is usually 1 or less.

The ethylene unit content of the terpolymer is usually 60 to 95 molti, preferably 50 to 85 molti, and the α-olefin unit content is usually 5 to 70 molti, preferably 15 to 50 molti.
Molty, non-conjugated diene unit content is usually 1 to 10 molty, preferably 3 to 6 molty, Mooney viscosity (Jf
L, , (100C)] is usually 5 to 200, preferably 40 to 120, and the iodine value is usually 1 to 50, preferably,
It is 5-30.

Preferred binary copolymers are ethylene-propylene copolymer (EPM) or ethylene-1-butene copolymer (EBM).
), ethylene unit content 50 to 95 mol, crystallinity 20 mol or less, melt flow rate), (1900)
0.1~2C1/10 order, (23011;)0.1~5
01/It's something I hate.

Preferred terpolymers are ethylene-propylene-dicyclopentadiene copolymer, ethylene-propylene-2-ethylidene-5-norbornene copolymer, ethylene-1-butene-dicyclopentadiene copolymer, or ethylene-propylene-dicyclopentadiene copolymer. A 1-butene-2-ethylidene-5-norbornene copolymer having an ethylene unit content of 50 to 50.
95 molty, propylene unit or 1-butene unit content 5-50 molty, remainder non-conjugated diene, crystallinity 20 inches or less, Mooney viscosity ML1+, (100C) 40-12
0, and an iodine value of 5 to 60.

Propylene which is the (h> component of the composition of the present invention - carbon number 4
The above α-olefin-based low crystalline copolymers and haflopyrene, such as 1-butene, 4-methyl-1-pentene, 1
- Obtained by copolymerization with one or more α-olefins such as octene and 1-decene, and whose crystallinity measured by X-ray diffraction is usually 40% or less, preferably 30% or less. means.

The propylene unit content is usually 40 to 90 moles, with the remainder being α-olefin having 4 or more carbon atoms. α-I7
When two or more types of olefins are used, the total amount is the α-olefin amount.

Melt flow rate of copolymer [MFRC250C]
is usually 0.1 to 200 f/10, preferably 1 to 40
r/10m.

A preferred copolymer is a globylene-1-butene copolymer, which has a propylene unit content of f[55 to 85 molt, a crystallinity of 10 to 50 t, and a melt flow rate of 1 to 40 f/
It is 10m long. Such copolymers are described, for example, in Japanese Patent Publication Nos. 57-11322 and 57-36859.

The organic peroxide, which is a typical radical generator used to produce the composition of the present invention, is one that decomposes in the temperature range above the softening point of the polymer component that is the least softened among the components. This is sufficient for the purposes of the present invention.

Examples of organic peroxides include the following.

Aromatic compounds include dibenzoyl peroxide,
Dicumyl peroxide, 1,6-bis(t-butylperoxyisopropyl)benzene (trade name Percadox 14), aliphatic compounds include di-t-butyl peroxide, dilauroyl peroxide, 2,5-dimethyl-2 , 5-bis(t-butylperoxy)hexane (trade name Perhexa 25B), 2,5-dimethyl-2,5-bis(t-butylperoxy)hexene-6,2,5-dimethyl-2゜5 -dimethyl-2,5
-bis(t-butylperoxy)hexyne-51 Product name perhexine], di(t-butylperoxy)perbenzoate, which belongs to both aromatic and aliphatic groups,
Examples of alicyclic compounds include p-menthane peroxide and the like.

Among these, preferred are bisperoxide compounds.

Examples of the radically polymerizable monomer (d) having two or more polymerizable groups that may be used together with the radical generator in the method of the present invention include the following.

(d-1) Aromatic compound Nidivinylbenzene (DVB
), Improbenylstyrene, diisopropenylbenzene, Cd-2) Aliphatic compounds: ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, allyl methacrylate, (d-3) heterocyclic group Series compound: triallyl in cyanurate.

Among these, preferred are p-divinylbenzene and p-diisopropenylbenzene.

Furthermore, a crosslinking aid may be used during the partial crosslinking treatment. Examples include p-quinonedioxime, p, p
'-Shichenzoylquinonedioxime, N-methyl-#
+ 4- dinitrosoaniline, nitrobenzene, diphenylguanidine, trimethylolpropane-N,
A''-m-phenylene dimaleimide and the like can be mentioned.

The amounts of each component constituting the composition of the present invention are as follows. Radically decomposable crystalline polyolefin (C) usually 0 to 90 parts by weight, preferably 10 to 6o parts by weight,
Ethylene-α-olefin amorphous copolymer (α) usually 10 to 95 parts by weight, preferably 40 to 90 parts by weight, propylene-α-olefin low crystalline copolymer having 4 or more carbon atoms <b >Usually 5 to 90 parts by weight, preferably 10 to 6 parts by weight
It is convenient to select the weight in such a way that the sum of the weights is 100 parts by weight.

Usually 0.05 to 3 parts by weight, preferably 0.01 to 3 parts by weight, respectively, per 100 parts by weight of an organic peroxide, which is a typical radical initiator, and a radically polymerizable monomer having two or more polymerizable groups.
~1 part by weight.

In the method of the present invention, dynamic heat treatment refers to the following treatment.

The polymer components to be treated, that is, a radically decomposable crystalline polyolefin (C) and an ethylene-α-olefin amorphous copolymer (cL) are combined, and an organic peroxide or two or more polymerizable polymers are added to this. A system obtained by adding a radically polymerizable monomer (CL) having a group in a molten state,
Knead under the decomposition conditions of (C).

Of course, the propylene-α-olefin low-crystalline copolymer with 4 or more carbon atoms also contains a radically decomposable propylene chain. - Olefin-based amorphous copolymer (α) and propylene-α-olefin-based low crystalline copolymer (h) having 4 or more carbon atoms are heated and kneaded under radical-generating conditions to form propylene chains in both components. There is no problem with a method of partially cross-linking the material through the resin.

Note that the radical generation conditions include not only conditions in which a radical generator is simply added and it decomposes to generate radicals, but also conditions in which radicals are generated by irradiation with ionizing radiation, electron beams, etc. It is a concept.

The kneading is preferably carried out in a closed type apparatus, preferably under an atmosphere of an inert gas such as nitrogen or carbon dioxide. The temperature is such that the half-life of the organic peroxide used is less than 1 minute, usually 150 to 280 tZ', preferably 170 to 240 tr, and the crosstalk time is usually 1 to 20 minutes, preferably 1. < is 6 to 1 minutes. Further, the shearing force to be applied is usually selected at a shear rate of 10 to 10'sec', preferably (7< is selected to be 102 to 10'sec').

As the mixing device, a mixing roll, an intensive mixer such as a Banbury mixer, a Niegoo, a double-screw extruder, or a twin-screw extruder can be used, but a non-open type is preferable.

The compositions of the present invention may further include softeners (also known as extender oils or plasticizers), carbon black, white carbon, other property modifiers, fillers and anti-aging agents, oxidation, weathering or light stabilizers, processing aids. , antistatic agents, pigments, etc. are added depending on the purpose [2.

Reference example 1゜Ethylene-propylene- with ethylene content 78 molt, iodine number 15, Mooney viscosity ML1+4 (100c) 70
75 parts of 2-ethylidene, 5-norbornene copolymer rubber (hereinafter abbreviated as EPDM), melt flow rate (M
FR) (230t;, 2.16Kg) 11, density 0.9
15 parts of crystalline polypropylene (hereinafter abbreviated as PP) of No. 1,
10 parts of isobutyne-imprene copolymer rubber (hereinafter abbreviated as 11R), tetrakis [methylene (
3,5-di-t-7”thyl-4-hydroxyphenyl)
Add 0.6 parts of Probionate 3F 5F to Banbury mixer.
After kneading at 180C for 15 minutes under nitrogen atmosphere,
A pellet was produced by passing it through a roll and using a sheet cutter. Next, the pellets were mixed with a solution prepared by dissolving and dispersing 0.5 M of 1,3-bis(tert-butylperoxyisopropyl)benzene in 0.5 parts of divinylbenzene using a Henschel mixer, and the solution was applied to the surface of the pellets. It adhered evenly. The pellets were then extruded under a nitrogen atmosphere at 21 DC.

Extrusion with a residence time of 5 minutes and dynamic heat treatment yielded a thermoplastic elastomer.

This thermoplastic elastomer was molded using an injection molding machine to obtain a sheet measuring 12Dx100x2.

Next, a test piece with a width of 25 mm was cut out from this sheet, and the stress at breakage was measured by tensile in the length direction, which was 40 KI/c.
It was A. Further, its gloss (cross) was 8%.

Example 1 Ethylene-propylene-2-ethylidene-5-norbornene-based EpDM with ethylene content 78 molt, iodine number 15, Mooney viscosity ML 1+ll (100C) 70
70# Propylene-1-butene low crystalline copolymer pellet [propylene unit content 70 molt, #F/? (23
0C) 7f/10m] 30 parts and tetrakis[methylene (
3,5-di-b-butyl-4-hydroxyphenyl)propionate] 0.3 part of methane was mixed with a Banbury mixer under a nitrogen atmosphere at 180 tons? , after kneading for 5 minutes,
Pellets were produced by passing through a roll and using a sheet cutter. Next, 100 parts of the pellets and a solution prepared by dissolving and dispersing 0.6 parts by weight of 1,3-bis(tert-butylperoxyisopropyl)benzene in 0.5 parts by weight of divinylbenzene were mixed using a Henschel mixer. was applied uniformly to the pellet surface. The pellets were then extruded under a nitrogen atmosphere at 21 DC.

A thermoplastic elastomer was obtained by extrusion with a residence time of 5 minutes and dynamic heat treatment. The strength at break was measured by the method of Reference Example 1 and was 90 Kg/Cn.

Cutting the injection molded sheet obtained in Reference Example 1 in half 17,
After the sheet was loaded into a split mold, the thermoplastic elastomer of Example 1 was injection welded, and the bonding strength between the two was measured. The surface gloss of the welded part was measured based on JIS Z8741. The results are shown in Table 2.

Comparative Example 1 Injection welding of the thermoplastic elastomer obtained in Reference Example 1 in Example 1] 7 Measurement of joint strength 1-.

The results are shown in Table 2.

Example 2 80 parts by weight of the thermoplastic elastomer obtained in Reference Example 1 and 7 f of propylene-1-butene low crystalline copolymer pellets (propylene unit content 70 moles, MF1230C)
/10 parts] in a Henschel mixer, and then the pellets were mixed in an extruder under a nitrogen atmosphere for 21 parts by weight.
Extrusion was carried out at 0C with a residence time of 5 minutes to obtain the desired composition.

The injection molded sheet obtained in Reference Example 1 was cut in half, and the sheet was loaded into a split mold.The thermoplastic elastomer composition of Example 2 was then injection welded and the joint strength was measured. The gloss of the welded area was measured based on JIS Z8741. The results are shown in Table 2.

Comparative Example 2゜MFR (1 part) was used instead of 20 parts of pBR in Example 2.
The thermoplastic elastomer was obtained using 20 parts of an ethylene-vinyl acetate copolymer resin (hereinafter abbreviated as EVA) having a density of 0.93 and an acetic acid content of 14 ruin. The injection molded sheet obtained in Reference Example 1 was cut in half, and the sheet was molded and loaded into a split mold, and then the thermoplastic elastomer composition of Comparative Example 2 was injection welded and the joint strength was measured. The results are shown in Table 2.

Table 2 Table 2 shows that the composition of the present invention can be firmly injection-welded to a molded article made of a thermoplastic elastomer.

That is, the strength at break of the bonding strength sheets in Examples 1 and 2 was evaluated to be 28 odors/CrI and 3 CrI, respectively.
2Ky/cr/I, and the stresses at break in Comparative Examples 1 and 2 were approximately 2Kg/CIA and 15Kg/d, respectively.
Not only has the bond increased by twice as much, but the state of the rupture is also partially material failure, which indicates that the bonding is not just adhesion, but also involves the fusion of the two materials at the bonded portion.

Furthermore, since the reference example is the breaking strength of veneer, the breaking strength of each example reaches 70% and 80% of the corresponding value of veneer, respectively, which indicates that surprisingly strong fusion is achieved between dissimilar materials. 0, which is evidence that it has been formed Patent applicant Mitsui Petrochemical Industries Co., Ltd. Patent attorney Ikuo Tsuchi Suzuki

Claims (2)

[Claims] (1) Ethylene-α-olefin amorphous co-ipolymerization (α
) and a propylene-α-olefin low crystalline copolymer having 4 or more carbon atoms (b), both of which are partially crosslinked via propylene chains. Thermoplastic elastomer composition with good properties and gloss. (2) Ethylene-α-olefin amorphous + [coalescence (α
) and a partially crosslinked thermoplastic elastomer obtained by heating and kneading a composition consisting of a radically decomposable crystalline polyolefin (C) under radical-generating conditions, and prohylene - an α-olefin having 4 or more carbon atoms. A method for producing a thermoplastic elastomer composition with excellent injection fusion properties and gloss, which comprises melting and kneading a low-crystalline copolymer (h).