JPH0826196B2 - Thermoplastic elastomer composition - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic elastomer composition containing chlorinated polyethylene as a resin component, which is excellent in compression set and has good strength and processability.

[0002]

2. Description of the Related Art The demand for improved performance of elastomer materials is increasing year by year, and particularly in the automobile field, excellent compression set is required as a material for glass run channels and drainers.

Conventionally, a soft vinyl chloride resin as such a material has a soft rubber-like feel, is excellent in moldability, weather resistance, colorability, etc. as compared with a vulcanized rubber, and is also cost effective. It has been used extensively. However, compression set is inferior to vulcanized rubber, and the softening temperature is low, so that use at high temperatures is restricted. Therefore, attempts have been made to improve the vinyl chloride resin to have a high degree of polymerization, but no satisfactory one has been obtained.

Various methods have been proposed to improve the compression set by adding nitrile rubber having a crosslinked structure to vinyl chloride resin, but these compositions are inferior in processability, and the compression set and weather resistance are poor. It was difficult to satisfy both sexes at the same time. Furthermore, chlorinated polyethylene as a resin component,
An attempt to improve the compression set is disclosed in JP-A-62-20547, which contains a vinyl chloride resin,
And it is essential to crosslink the vinyl chloride resin,
Sufficient compression set cannot be obtained without crosslinking, and the technical idea of improving the compression set with a composition comprising chlorinated polyethylene and a plasticizer has not been shown.

[0005]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention As a result of intensive investigations by the inventors of the present invention, a method of improving the compression set without undergoing a vulcanization or crosslinking reaction in a composition comprising chlorinated polyethylene and a plasticizer. , A crystalline chlorinated polyethylene having a specific degree of chlorination and a heat of crystal fusion obtained by chlorinating a polyethylene having a specific molecular weight and a plasticizer are kneaded under heating while applying a shearing force, which is extremely excellent. It was found that a composition exhibiting compression set and strength was obtained, and by further adding an organophosphoric acid metal salt having a specific structure to the composition, the composition did not adhere to the kneader during kneading, and processing was easy. The present invention has been completed by finding out that it can be carried out and the weather resistance is improved.

That is, the object of the present invention is to provide a compression set,
Another object of the present invention is to provide a thermoplastic elastomer composition which is excellent in strength and weather resistance and which can be easily processed.

[0007]

However, the gist of the present invention is that the chlorination degree obtained by chlorinating polyethylene having a molecular weight of 100,000 to 200,000 is 20 to 45%, and the DSC method heat of fusion of crystals is 5 -35 cal / g crystalline chlorinated polyethylene 100 parts by weight and a plasticizer 15-60 parts by weight, and a thermoplastic elastomer composition characterized by the following general formula (1) or (2): The present invention is a thermoplastic elastomer composition containing 0.1 to 10 parts by weight of the organophosphoric acid metal salt represented.

[0008]

Embedded image

(In the formula, R ₁ and R ₂ are each an alkyl group, an aryl group, an arylalkyl group, an alkylaryl group or an alkyl group having an ether bond,
Each R ₁ may be different. M represents zinc, magnesium, calcium, barium, cobalt or strontium. )

The present invention will be described in detail. The crystalline chlorinated polyethylene used in the present invention is obtained by post-chlorinating polyethylene having a molecular weight of 100,000 to 200,000,
Chlorination degree 20-45% and heat of DSC crystal fusion 5-35
It is necessary that cal / g, preferably 5 to 25 cal / g, is used. The heat of fusion of this crystal has a crystal residue of polyethylene, that is, a so-called crystallinity of 10 to 75%, preferably 10 to 50%. % Range is preferred. The molecular weight of polyethylene is shown by the weight average molecular weight.

If the molecular weight of polyethylene is less than 100,000, the tensile strength will be weak, and if it exceeds 200,000, the melt viscosity will be high and the processability will be poor, such being undesirable. DSC method heat of fusion of crystals measured by DS using a differential calorimeter at a heating rate of 10 ° C / min.
The value calculated from the total crystal peak area of C chart,
If it is less than 5 cal / g, it means that there is substantially no residual crystal. Further, the DSC method crystal melting point described later is the temperature at which the highest peak among all the crystal peaks at the time of DSC method crystal fusion heat measurement is shown. The crystalline melting point of the chlorinated polyethylene used in the present invention is in the range of 110 to 140 ° C.

If the degree of chlorination of chlorinated polyethylene is less than 20%, the compatibility with the plasticizer is poor, the hardness cannot be lowered, and the weather resistance is poor. On the other hand, if it exceeds 45%, the rubber elasticity is lowered, and the purpose is And the compression set cannot be obtained. If the heat of crystal fusion is less than 5 cal / g, the effect of improving compression set is lost, while if it exceeds 35 cal / g, the hardness cannot be lowered, and the amount of plasticizer absorbed during processing is small. Bleed phenomenon occurs due to poor compatibility with plasticizers at room temperature.

The plasticizer used in the present invention is not particularly limited as long as it is used for vinyl chloride resins.
For example, phthalate ester plasticizers such as di-2-ethylhexyl phthalate, di-n-octyl phthalate, diisodecyl phthalate, dibutyl phthalate, dihexyl phthalate; linear dibasic ester ester plasticizers such as dioctyl adipate and dioctyl sebacate; Trimellitic acid ester plasticizers; polyester polymer plasticizers; epoxy plasticizers such as epoxidized soybean oil, epoxidized linseed oil and epoxy resins; phosphoric acid such as triphenyl phosphate, trixylyl phosphate, tricresyl phosphate Ester-based plasticizers may be used, and one or more of these may be mixed and used.

The amount of the plasticizer used is appropriately determined depending on the additives used in combination or the hardness of the intended product.
It is selected from the range of 15 to 60 parts by weight, especially 20 to 55 parts by weight, relative to 100 parts by weight of chlorinated polyethylene. For example, in a composition to which an inorganic filler is not added, that is, a composition consisting only of chlorinated polyethylene and a plasticizer, the amount of the plasticizer to be used should be limited to 50 parts by weight or more. Kneading becomes difficult due to the blowing out. By using an inorganic filler, it is possible to add up to 60 parts by weight. If the amount of the plasticizer is too small, only the one having high hardness can be obtained, and conversely, if the amount is too large, bleeding out occurs, which is not preferable.

R ₁ and R of the organophosphoric acid metal salt represented by the general formulas (1) and (2) used in the present invention.
₂ is, for example, methyl group, ethyl group, (iso) propyl group, (iso) butyl group, neopentyl group, (iso) hexyl group, (iso) octyl group, decyl group, lauryl group,
Alkyl groups such as tridecyl group, stearyl group, cyclohexyl group, cyclodecyl group, aryl groups such as phenyl group, naphthyl group, benzyl group, β-phenylethyl group, α
An arylalkyl group such as a phenylpropyl group and a β-phenylpropyl group, a tolyl group, a xylyl group, an ethylphenyl group, a butylphenyl group, a third octylphenyl group,
Alkylaryl groups such as nonylphenyl group, 2,4-tert-butylphenyl group, furfuryl group, tetrahydrofurfuryl group, 5-methylfurfuryl group, α-methylfurfuryl group, and other alkyl groups having an ether bond, etc. Named

Further, various cellosolve residues such as methyl cellosolve, ethyl cellosolve, cyclohexyl cellosolve and phenyl cellosolve, various ether residues such as dimethyl ether, methyl ethyl ether, methylhexyl ether, dicyclohexyl ether and butyl cyclohexyl ether, glycerin-1,2- It may be various glycerin ether residues such as dimethyl ether and glycerin-1,3-dimethyl ether, and various polyethoxyethyl residues such as nonylphenoxypolyethoxyethyl and lauroxypolyethoxyethyl.

The organophosphoric acid metal salt is usually produced as a mixture of compounds having the structures of the general formulas (1) and (2), and it is used without separation. The amount of the organophosphate metal salt compounded is 0.1 to 1 with respect to 100 parts by weight of chlorinated polyethylene.
A range of 0 parts by weight, preferably 0.2 to 5 parts by weight is suitable. If the blending amount is less than 0.1 part by weight, the composition adheres to the kneading machine during the kneading of the composition, the effect of improving the workability is small, and the effect of improving the weather resistance cannot be expected. On the other hand, even if more than 10 parts by weight is used, it does not show the effect of improving the workability in proportion to the blending amount, and it is preferable to set the content within the above range from the economical point of view.

An inorganic filler may be added to the composition of the present invention within a range that does not impair the compression set. With respect to 100 parts by weight of the crystallized chlorinated polyethylene, the compression set is improved according to the addition amount of the plasticizer up to about 60 parts by weight of the plasticizer. However, when the amount of the plasticizer is more than 50 parts by weight, the plasticizer is released from the chlorinated polyethylene and the kneading becomes difficult, and the plasticizer bleeds from the molded article obtained from the composition. In order to prevent this bleeding phenomenon, it is desirable to add an inorganic filler such as calcium carbonate or talc. The inorganic filler has a function of absorbing an excessive amount of plasticizer and facilitating kneading. Then, the addition amount is 100% of crystalline chlorinated polyethylene.
100 parts by weight or less, preferably 10 to 6 parts by weight
A range of 0 parts by weight is suitable.

The thermoplastic elastomer composition of the present invention may optionally contain various additives such as stabilizers, lubricants, antioxidants, ultraviolet absorbers, foaming agents, flame retardants, pigments and impact modifiers. May be.

In order to produce the thermoplastic elastomer composition of the present invention, the crystalline chlorinated polyethylene and the plasticizer and, if necessary, the above-mentioned various additives are heated to a temperature above the crystalline melting point of the crystalline chlorinated polyethylene. However, it is desirable to knead under shearing force. By kneading under these conditions, an elastomer composition having an excellent compression set can be obtained. At a temperature below the crystalline melting point, the plasticizer penetrates only into the amorphous part of the crystalline chlorinated polyethylene, and the crystal structure after kneading does not change, but it is heated to a temperature above the crystalline melting point and kneaded under shearing force. As a result, when the plasticizer penetrates into the crystal part and the chlorinated polyethylene is recrystallized, the plasticizer is extruded into the amorphous part and a network structure between the molecular chains is generated. It is presumed that elasticity is improved.

The equipment used to mix the above-mentioned ingredients may be any equipment that allows for substantially uniform mixing, such as a Henschel mixer, ribbon blender,
A planetary mixer or the like can be used. To knead the mixture, for example, an extruder, roll, Banbury mixer, kneader, or other device capable of kneading under heating while being heated is used. As a kneading method, it is also possible to adopt a method in which a chlorinated polyethylene and various additives are charged in the former stage and an plasticizer is injected in the latter stage using an extruder having multi-stage addition ports. The upper limit of the heating temperature is preferably within a range in which deterioration of chlorinated polyethylene can be ignored, specifically, 210 ° C or lower. The kneading temperature is in the range of 130 to 210 ° C, preferably 150 to 200 ° C.

[0022]

INDUSTRIAL APPLICABILITY The thermoplastic elastomer composition of the present invention has a smaller compression set as a plasticizer is added to chlorinated polyethylene, and is obtained by chlorinating polyethylene having a molecular weight of 100,000 to 200,000. By using the chlorinated polyethylene, the physical properties such as tensile strength are improved, and the addition of the organophosphoric acid metal salt allows the composition to be, for example, Banbury mixer, roll, extruder, etc. It does not adhere to the kneading machine, and the processability is improved and the weather resistance of the composition is improved.

Further, the composition of the present invention is kneaded under shearing force at a temperature not lower than the crystal melting point of chlorinated polyethylene, whereby the compression set is dramatically improved without adding a vulcanizing agent or a crosslinking agent. It is particularly useful as a material for glass run channels, drainers, boots, etc., which are installed in automobiles, and in fields requiring rubber elasticity such as packing.

[0024]

Next, the present invention will be described in detail with reference to examples, but the present invention is not limited to the following examples unless departing from the gist of the present invention. In addition, "part" and "%" in the examples
Is by weight unless otherwise noted. Further, the quality evaluation of the thermoplastic elastomer composition was performed as follows, and is shown in Table 2.

Hardness: JIS A hardness measured according to JIS K6301 on a test piece similar to that used for measuring compression set. Measurement of compression set: 70 based on JIS K6301
Measured at 25 ° C for 22 hours at 25 ° C. Bleed: A test piece similar to that used for the measurement of compression set was left in a thermo-hygrostat at 50 ° C. × 60% RH for 1 week, then left at 23 ° C. × 1 hour, and the surface bleed was visually observed. ○ → no bleed × → bleed

Weather resistance: The discolored state of the test piece after 1000 hours was visually observed and evaluated with a sunshine weatherometer. ○ → no discoloration × → discolored to brown Workability: The mixture in a beaker was put into a Brabender plastograph, and after kneading for a predetermined time, the degree of adhesion in the cell and the rotor was visually evaluated. -> Good viscosity, easy processing, no sticking to equipment, and good peeling. ○ → The viscosity is appropriate and easy to process, and there is no sticking to the equipment, but peeling is slightly inferior. × → The viscosity is too high, resulting in poor processability or sticking to equipment. Tensile test: Based on JIS K 6301, JIS No. 3 dumbbell pieces were punched out from the sheet, and the pulling speed was 200 mm.
/ Min, 23 ° C Tensilon tensile tester UTM-III-
The breaking strength was measured using 100.

Examples 1 to 9 and Comparative Examples 1 to 7 Chlorinated polyethylene (CPE) of the types and addition amounts (parts by weight) shown in Table 1, plasticizers, inorganic fillers (fillers) and organophosphate metal salts. (Phosphate) and 2 parts of lead-based powder stabilizer are mixed in a beaker, and the mixture is kneaded with a Brabender Plastograph with a cell temperature of 150 ° C. for 50 minutes for 50 minutes, and further with a mill roll having a surface temperature of 130 ° C. The sheet was obtained by kneading for 5 minutes. This sheet was further pressed at 180 ° C. for 5 minutes to prepare a test piece having a predetermined thickness. The quality evaluation described above was performed on this test piece.

Comparative Example 8 For 100 parts of vinyl chloride resin having an average degree of polymerization of 2500,
Plasticizer (DOP) 100 parts, tetrahydrofuran (TH
F) 100 parts of partially cross-linked NBR having a solubility of 20% and 3 parts of dibutyltin maleate were mixed with a mill roll at 180 ° C. for 10 minutes.
The sheet was prepared by kneading for minutes. The sheet is shown in Example 1.
A press test piece was prepared in the same manner as described above and subjected to quality evaluation. The evaluation results are also shown in Table 2.

[0029]

[Table 1]

* 1: Shower Denko chlorinated polyethylene A: Erasulene 202B (polyethylene molecular weight 12
10,000, chlorination degree 23%, heat of crystal fusion 17 cal / g, crystal melting point 125 ° C) B: Erasulene 302B (polyethylene molecular weight 12
10,000, chlorination degree 31%, crystal fusion heat 13 cal / g, crystal melting point 125 ° C) C: Eraslen 303B (polyethylene molecular weight 70,000,
Chlorination degree 30%, heat of crystal fusion 12cal / g, crystal melting point 12
3 ° C) D: Erasulene 301B (polyethylene molecular weight 23
10,000, chlorination degree 31%, heat of crystal fusion 9cal / g, crystal melting point 1
25 ° C) E: Erasulene 302NA (polyethylene molecular weight 12
10,000, chlorination degree 31%, heat of crystal fusion 0.5 cal / g or less, amorphous) * 2: L: di-2-ethylhexyl phthalate M: di-isononyl adipate * 3: G: calcium carbonate H: talc * 4 : X: Zinc salt of stearyl phosphate Y: Barium salt of palmityl phosphate

[0031]

[Table 2]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display location C08K 5/527 // C08L 23:28 (72) Inventor Naoki Ichikawa Iwatsuka-cho, Nakamura-ku, Nagoya-shi, Aichi Oike No. 2 Mitsubishi Kasei Vinyl Co., Ltd. Nagoya Plant (72) Inventor Mizuo Sumi Oike No. 2 Oike, Iwazuka-cho, Nakamura-ku, Nagoya, Aichi Prefecture Mitsubishi Kasei Vinyl Co., Ltd. Nagoya Plant (56) Reference JP-A-4-335047 (JP) , A)

Claims (4)

[Claims] 1. A crystalline chlorinated polyethylene 1 having a chlorination degree of 20 to 45% obtained by chlorinating polyethylene having a molecular weight of 100,000 to 200,000 and a DSC method heat of fusion of crystal of 5 to 35 cal / g.
A thermoplastic elastomer composition comprising 00 parts by weight and 15 to 60 parts by weight of a plasticizer. 2. The organic phosphate metal salt represented by the following general formula (1) or (2) is contained in an amount of 0.1 to 10 parts by weight.
The thermoplastic elastomer composition described. Embedded image (In the formula, R ₁ and R ₂ are each an alkyl group, an aryl group, an arylalkyl group, an alkylaryl group or an alkyl group having an ether bond, and R ₁ may be different from each other. M is zinc ,magnesium,
Indicates calcium, barium, cobalt or strontium. ) 3. The thermoplastic elastomer composition according to claim 1, which contains 10 to 100 parts by weight of an inorganic filler. 4. A crystalline chlorinated polyethylene 1 obtained by chlorinating polyethylene having a molecular weight of 100,000 to 200,000 and having a chlorination degree of 20 to 45% and a DSC method heat of fusion of crystal of 5 to 35 cal / g.
A method for producing a thermoplastic elastomer composition, which comprises kneading a mixture containing 00 parts by weight and 15 to 60 parts by weight of a plasticizer at a temperature equal to or higher than the crystalline melting point of crystalline chlorinated polyethylene under shearing force.