JPH02283754A - Thermoplastic elastomer composition - Google Patents

Abstract

PURPOSE:To prepare a thermoplastic elastomer compsn. useful for producing automobile and industrial parts excellent in the resistance to heat, light, and weathering by compounding a polyetherester block copolymer with a stabilizer comprising a combination of specific compounds. CONSTITUTION:A polyetherester block copolymer is compounded with a stabi lizer comprising (A) a hindered phenol having a structure with a center of symmetry and two to four hindered phenol groups of the formula (wherein R and R' are each a 1-12C hydrocarbon group and at least one of them is a 4-12C hydrocarbon group; and (n) is 0-3) in the molecule, e.g. triethylene glycol bis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate]; a benzotriazole having no substituent on the benzotriazole ring, e.g. 2-(2'-hydroxy-5'-methylphenyl) benzotriazole; and a hindered amine (e.g. 4-benzoyloxy-2,2,6,6-tetramethyl- piperidine). Thus a thermoplastic elastomer compsn. excellent in the resistance to heat, light, and weathering is prepd.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a stabilized composition of a thermoplastic elastomer comprising a polyether ester block copolymer, and more specifically, it relates to a stabilized composition of a thermoplastic elastomer comprising a polyether ester block copolymer, and more specifically, it has excellent heat resistance, light resistance, This invention relates to a polyester thermoplastic elastomer composition useful for automotive parts and industrial parts with excellent weather resistance.

[Prior Art] Polyester thermoplastic elastomers, which are composed of polyether segments that act as soft segments and polyester segments that act as hard segments, have the highest heat resistance, oil resistance, and It has excellent mechanical properties and is being used in high-performance applications such as automobile parts and industrial parts where these properties are important.

However, in polyether ester type polyester thermoplastic elastomers, the polyether part of the soft segment in the main chain is susceptible to oxidative deterioration due to heat and light, and the degree of polymerization decreases due to decomposition and deterioration of the main chain, resulting in mechanical damage. These problems include deterioration of properties, occurrence of cracks on the surface of the molded product, and significant discoloration. Therefore, the current situation is that outdoor exposure or long-term use in high-temperature atmospheres is restricted.

Therefore, for the purpose of preventing these deterioration phenomena, it is being considered to add various stabilizers to thermoplastic elastomers of polyether ester copolymers. Among these, to prevent thermal oxidative deterioration and improve heat resistance, it is common to add antioxidants such as hindered phenol compounds, arylamine compounds, thioether compounds, and phosphite compounds. To obtain a thermoplastic elastomer composition of a polyether ester block copolymer which has no coloring and has excellent heat resistance, especially when a hindered phenol compound and a thioether compound are used in combination. It has been known.

On the other hand, in order to prevent photooxidative deterioration and improve weather resistance, UV absorbers such as benzotriazole compounds and benzophenone compounds, or hindered amine light stabilizers whose light stabilization mechanism is completely different from that of UV absorbers, are recommended. It is common to add radical-scavenging photostabilizers such as, among others, hindered amine photostabilizers are particularly useful for protecting exposed surfaces, maintaining white discoloration, and maintaining mechanical properties. It also has superior effects over ultraviolet absorbers in terms of evaluation criteria.

However, when a phenol compound and a thioether compound, which are highly effective in improving heat resistance, are further combined with a hindered amine light stabilizer, which is highly effective in improving weather resistance, the thioether compound and hindered amine light stabilizer The effect of the hindered amine light stabilizer is significantly impaired due to the interaction with the curing agent, resulting in a composition with unsatisfactory weather resistance.

In addition, by combining a hindered phenol compound with a peroxide decomposer such as a thioether compound or a thiophosphite compound, and an ultraviolet absorber such as a benzotriazole compound or benzophenone compound, heat and light Attempts have also been made to create a polyester thermoplastic elastomer composition of a polyether ester block copolymer that is stable against It was insufficient in terms of maintenance, etc.

[Problems to be Solved by the Invention] The present invention is capable of stabilizing molded products with small changes in appearance, coloration, and mechanical properties even under environmental conditions such as high temperatures and light irradiation, which cannot be achieved with conventional stabilizer combinations. An object of the present invention is to provide a polyester thermoplastic elastomer composition comprising a polyether ester block copolymer.

[Means for Solving the Problems] The polyester thermoplastic elastomer composition comprising the polyether ester block copolymer of the present invention has (A) a symmetry center structure, and in the molecule (in the formula, R, R' is a hydrocarbon group having 1 to 12 carbon atoms; at least one of RSR' is a hydrocarbon group having 4 to 12 carbon atoms; A thermoplastic elastomer composition is provided, in which a stabilizer consisting of a hindered phenol compound having four benzotriazole rings (B), a benzotriazole compound having no substituent on the benzotriazole ring, and (C) a hindered amine compound is added.

The polyether ester block copolymer in the present invention is a block copolymer consisting of a polyester hard segment and a polyether soft segment having a number average molecular weight of 200 to 6,000, and the ratio of the hard segment to the soft segment is 10. ~90% by weight vs. 90-10
% by weight.

The dicarboxylic acid component forming the polyester hard segment includes terephthalic acid, isophthalic acid, phthalic acid, 2,6- and 1,5-naphthalenedicarboxylic acid, bis(p-carboxyphenyl)methane, anthracenedicarboxylic acid, 4゜4 Aromatic dicarboxylic acids such as '-diphenyl ether dicarboxylic acid, 4゜4'-diphenylmethane dicarboxylic acid, phenylindane dicarboxylic acid,
Alicyclic dicarboxylic acids such as 1.4-cyclohexanedicarboxylic acid, cyclopentanedicarboxylic acid, and 4.4'-dicyclohexyldicarboxylic acid, and aliphatic dicarboxylic acids such as adipic acid, sebacic acid, azelaic acid, dimer acid, etc. However, from the viewpoint of mechanical properties and heat resistance, it is preferable to use aromatic dicarboxylic acid in an amount of at least 50 mol %, and use of terephthalic acid is particularly recommended.

In addition, the diol components constituting the hard segment include aliphatic or alicyclic diols having 2 to 12 carbon atoms;
i.e. ethylene glycol, propylene glycol,
1.4-butanediol, neopentyl glycol, 1
．． 5-bentanediol, 1,6-hexanediol,
Decamethylene glycol, cyclohexane dimetatool, bisphenols such as bis(p-hydroxy)diphenyl, bis(p-hydroxyphenyl)titanium, bis(p-hydroxyphenyl)propane, and mixtures thereof can be used; 2-8 aliphatic or cycloaliphatic diols are preferably used.

In addition, the poly(alkylene oxide) glycol constituting the polyether soft segment includes polyethylene glycol, poly(1,3- or 1,2-propylene glycol), poly(tetramethylene oxide) glycol, polyethylene glycol-polypropylene glycol. These include block copolymers, polyethylene glycol-poly(tetramethylene oxide) glycol block copolymers, etc. Poly(tetramethylene oxide) glycol is particularly preferred, and of course a combination of these is also possible.The average of these polyether glycols Molecular weight ranges from about 200 to 6,000.

The polyether ester block copolymer made of these components can be produced by any method, but one example of a suitable polymerization method is to add dimethyl ester of dicarboxylic acid to an excess of molar amount, that is, about 1°2 to the acid. With ~2.0 times the mole of low-molecular weight glycol and poly(alkylene oxide) glycol, transesterification is carried out at a temperature of about 150 to 260°C under atmospheric pressure in the presence of a conventional esterification catalyst to perform transesterification. was distilled out, and then 5 mm1
It can be produced by heating polycondensation at 200 to 270° C. under reduced pressure of 1 g or less. If necessary, a polyfunctional copolymer component that can be partially chemically crosslinked, such as polycarboxylic acid, polyol, polyoxycarboxylic acid, etc., may be used in the polyether ester block copolymer.

It also constitutes one of the stabilizers used in the present invention (A
) The hindered phenol compound has a center-of-symmetric structure, and in one molecule (in the formula, R and R' are hydrocarbon groups having 1 to 12 carbon atoms, and at least one of R and R' is a carbon group). Numbers 4 to 12
hydrocarbon group, n=an integer of 0 to 3), preferably R, R' are 1 to 6 hydrocarbon groups, R, R' are At least one of them is a hydrocarbon group having 4 to 6 carbon atoms, n=l to 2, particularly preferably, R is -CH
3; tE or t-C4H9, R' is t-C4H9, n=
It is 1.

A preferred representative thereof is triethylene glycol-bis(3-(3-t-butyl-5-methyl-4-
hydroxyphenyl)probionate], triethylene glycol-bis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)butyrate], triethylene glycol-bis(3-(3-t-butyl- 5-methyl-4-hydroxyphenyl)valerate], triethylene glycol-bis(3-(3-t-butyl-5-methyl-4-hydroxyphenyl)caprony)), 1.
6-hexanethiolubis[3-(3,5-di-t-
butyl-4-hydroxyphenyl)propionate),
2.2-thio-diethylenebis[3-(3,5-di-t
-butyl-4-hydroxyphenyl)propionate]
,N.

N'-hexamethylenebis(3,5-di-t-butyl-
4-hydroxy-hydrocinnamamide), 3.9-bis[2-(3-(3-t-butyl-4-hydroxy-5-
methylphenyl)propionyloxy)-1,1-dimethylethyl]-2,4゜8.10-tetraoxaspiro(5,5)undecane, pentaerythrityl-tetrakis[3-(3,5-di-t- butyl-4-hydroxyphenyl) propionate], pentaerythrityl-tetrakis [3-(3,5-di-t-butyl-4-hydroxyphenyl)butyrate], pentaerythrityl-tetrakis (3-(3,5-di-t-butyl-4-hydroxyphenyl)butyrate) -t-butyl-4-hydroxyphenyl)valerate, pentaerythrityl-tetrakis(3-(3,5-di-t-butyl-4-hydroxyphenyl)caproate, octadecyl-3-(3,5-
Examples include di-t-butyl-4-hydroxyphenyl) propionate.

- Also, as a representative benzotriazole compound having no substituent on the benzotriazole ring (B), 2
- (2'-hydroxy-5'-methylphenyl)benzotriazole, 2- (2'hydroxyphenyl)
Benzotriazole, 2-(2'-hydroxy-3'
, 5'-dimethylphenyl)benzotriazole, 2-(2'-hydroxy-3'-t-butylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'di-t-butylphenyl)benzotriazole , 2-(2'-hydroxy-5'-ethoxyphenyl)benzotriazole, 2-(2'-hydroxy-5'-butoxyphenyl)benzotriazole, 2-(2'-hydroxy-3'5'-t
-amylphenyl)benzotriazole, 2-(2'
-Hydroxy-4'-octoxyphenyl)benzotriazole, 2-(2'-hydroxy-5'-t-octylphenyl)octylbenzotriazole, 2-[2
-Hydroxy-3,5-bis(α,α-dimethylbenzyl)phenyl]-2H-benzotriazole, 2-(
3,5-di-t-amy-2-hydroxyphenyl)benzotriazole, methyl-3-[3-t-butyl-5
-(2H-benzotriazol-2-yl)-4-hydroxyphenyl]propionate and polyethylene glycol) condensate, 2-2-methylenebis(4-(1,
1,3,3-tetramethylbutyl')-6-(2)(-
benzotriazol-2-yl)phenol), 2-(
Examples include hydroxy-3'(3'4',5'6'-tetrahydrophthalimido-methyl)-5'-methylphenyl-benzotriazole.

Furthermore, examples of the hindered amine compound (C) which is another component of the composition of the present invention include 4-benzoyloxy-2,2,6,6-titramethylpiperidine, bis(
2,2,6,6-tetramethyl-4-piperidinyl) carbonate, bis(2,2,6,6-tetramethyl-4
-piperidinyl)adipate, bis(2,2,6,6-
Tetramethyl-4-piperidinyl)sperate, bis(
2,2,6,6-tetramethyl-4-piperidinyl) sebacate, bis(2,2,6,6-tetramethyl-4-
piperidinyl) phthalate, bis(2,2,6,6-tetramethyl-4-piperidinyl)isophthalate, bis(2,2,6,6-tetramethyl-4-piperidinyl)
Terephthalate, tris(2,2,6,6-tetramethyl-4-piperidinyl)phosphite, 4-(N-phenylacetylamino)-2,2,6,6-tetramethylbiperidine, 4-(N -p-)luenesulfonylamino')-2,2,6,6-tetramethylbiperidine, N,
N'-bis(2,2,6,6-tetramethyl-4-piperidinyl)adipamide, bis(1,2,2,6,6-bentamethyl-4-piperidinyl)n-butyl(3,5-di-t-butyl- 4-hydroxybenzyl) malonate,
Bis(1,2,2,6,6-bentamethyl-4-piperidinyldibenzyl)malonate, bis(1°2.2,6
．． 6-bentamethyl-4-piperidinyl)bis(3,5
-di-t-butyl-4-hydroxybenzyl)malonate, bis(1,2,2゜6.6-bentamethyl-4-piperidinyl)diethylmalonate, bis(1,2,2,
6,6-bentamethyl-4-piperidinyl) n-dodecyl (3,5-di-t-butyl-4-hydroxybenzyl) malonate, bis(2,2,6,6-tetramethyl-
4-piperidinyl)bis(3,5-di-t-butyl-4-
hydroxybenzyl)malonate, bis(2,2,3,
6-tetramethyl-4-piperidinyl)dibenzylmalonate, bis(2,2,6,6-tetramethyl-4-piperidinyl)benzylethylmalonate, bis(2,2
゜6.6-tetramethyl-4-piperidinyl) 1-butyl (3,5-di-t-butyl-4-hydroxybenzyl) malonate, poly C(6-(1,1゜3.3-tetramethylbutyl) ) imino-1,3゜5-triazine-2
,4-diyl1((2,2゜6.6-tetramethyl-4
-piperidyl)imino)hexamethylene+ (2,2,
6,6-tetramethyl)imino]), N,N'-bis(
3-aminopropyl)ethylenediamine-2,4-bis(N-butyl-N-(1,2,2,6,6-bentamethyl-4-piperidyl)amino)-6-chloro-1°3.
5-1 riazine condensates, among others, bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, bis(1°2.2,6.6-bentamethyl-4-piperidinyl) ) n-butyl (3,5-di-
t-Butyl-4-hydroxybenzyl) malonate, poly [(6-(1,1,3,3-tetramethylbutyl)
imino-1,3,5-)riazine-2,4-diyl)+
(2,2,6,6-tetramethyl-4-piperidyl)
imino)hexamethylene + (2,2,6°6-tetramethyl)iminol:l,N,N'-bis(3-aminopropyl)ethylenediamine-2°4-bis[N-butyl-N-(1 ,2,2,6゜6-bentamethyl-4-
Piperidyl)aminoco-6-chloro-1,3,5-triazine condensate can be mentioned as a preferred compound.

For the purpose of the present invention, the above-mentioned stabilizer (A), (
The three components B) and (C) are essential, and if even one of these components is missing, the stabilizing effect aimed at by the present invention will not be achieved.

Among the hindered phenol compounds, the binder phenols having the structure (A) have better compatibility with the Rufo IJ ether ester block copolymer used in the present invention and antioxidant effects than other structural hindered phenols ( B)
, has an extremely strong synergistic stabilizing effect when used in combination with component (C).

In addition, the benzotriazole compound of component (B) has a smaller color change when added or after an environmental test if it does not have a substituent on the benzotriazole ring, and other components (A), (C
) This is because a synergistic effect occurs with the ingredients.

The amount of each of these stabilizers added is 0.05 parts by weight per 100 parts by weight of the polyether ester block copolymer.
-5 parts by weight, preferably 0.1-2 parts by weight.

There is no particular restriction on the method of adding the above-mentioned hindered phenol compound (B), benzotriazole compound (C), and hindered amine compound (D) to the polyether ester block copolymer. Although it can be added during or at any time after polymerization, a particularly preferred embodiment is a method of melt-mixing after polymerization (before molding).

In addition, when preparing the composition of the present invention, other common additives such as hydrolysis resistance improvers, colorants (pigments, dyes),
Additives such as a dispersant, an antistatic agent, a conductive agent, a crystal nucleating agent, a lubricant, a filler, a reinforcing material, an adhesion aid, a plasticizer, a mold release agent, and a flame retardant can be optionally blended.

[Example] The present invention will be specifically explained below using Examples.

Example 1 Commercially available polyether block copolymer (hard segment: main component is polybutylene terephthalate, soft segment: main component is polyester of polytetramethylene glycol and terephthalic acid, manufactured by Dutra 1, trade name PIBIFLEX 460M) 100 Pentaerythrityl-tetrakis [3-(3,5-di-t-butyl-
4-hydroxyphenyl)propionate) (Ch
Manufactured by iba Geigy, product name IRGANOX 10
10)0. 2 parts by weight, 2-[2-hydroxy-3°5-bis(α,α-dimethylbenzyl)phenyl]-2H-benzotriazole (manufactured by Chiba Geigy, trade name TlN0VIN) as a benzotriazole compound
234) 0. 2 parts by weight, as a hindered amine compound poly((6-(1,1,3°3-tetramethylbutyl)imino-1,3,5-triazine-2,4-diyl) ((2,2,6°6 -tetramethyl-4-piperidyl)imino)hexamethylene((2,2,6,6-
Tetramethyl-4-piperidyl)imino) ) (Ch
Manufactured by iba Geigy, product name Cfl1MASSOR
B 994LD) 0. Two parts by weight were kneaded using an extruder to produce pellets containing the stabilizer, and further a test piece for a tensile test was produced using an injection molding machine.

Tensile strength (T, ) and elongation at break (EB) were measured. Furthermore, the color difference of the test piece was measured using the test piece.

The test piece was subjected to an environmental test using a sunshine weather meter set at 83° C. for 96 hours (120 minutes with a rain cycle of 18 minutes). After the test, T8 and EB were measured by a tensile test, and the retention rate of the measured values after the test was determined.

TB or EB before environmental test The color difference in the test was also measured using a color difference meter.

The results are shown in Table-1.

Examples 2 to 6 As the stabilizers used in Example 1, the same amounts of hindered phenol compounds, benzotriazole compounds, and hindered amine compounds having the structures shown in Table 1 as in Example 1 were used, and tests were conducted in the same manner. .

The results are shown in Table-1.

Comparative Example 1 A test piece was prepared by molding the pellet as it was without using a stabilizer. The results are shown in Table-1.

Without adding stabilizers, the surface after environment will crack and
It can be seen that the mechanical properties deteriorate and the color change is large.

Comparative Examples 2 to 4 Among the three types of stabilizer combinations used in Example 1,
A similar evaluation was performed using a combination of the two types. Display the results -
Shown in 1.

It can be seen that the combination of three types of specific stabilizers according to the present invention reduces the decrease in mechanical properties and color change.

Comparative Example 5 Compound 2- (3
,5-di-t-butyl-2-hydroxyphenyl)-5
- Chlorobezotriazole (manufactured by Chiba Geigy, trade name TINUVIN 327) was replaced with the same evaluation. The results are shown in Table-1.

It can be seen that when a substituent is added to the benzotriazole ring, it is effective in maintaining mechanical properties after environmental testing, but it is not very effective in changing color difference.

Comparative Example 6 Instead of the hindered phenol compound used in Example 3, a hindered phenol compound 2,2'-methylenebis(4-methyl-5-
tert-butylphenol) (manufactured by Sumitomo Chemical Co., Ltd., trade name Sumilizer MDP-3) was used. The other evaluations were conducted in the same manner. The results are shown in Table-1.

It can be seen that unless a specific hindered phenol compound is used, deterioration of mechanical properties and color change after environmental testing cannot be prevented.

Examples 7 to 9 Black colorant 1 mainly composed of carbon black was added to the polyester elastomer 100 type assembly used in Example 1.
Examples 1 to 3 were added to black pellets mixed with parts by weight
The same evaluation was performed by adding the stabilizer used in 3. The results are shown in Table-2.

No cracks were observed on the surface of the test piece after the environmental test.

Comparative Example 7 Similar evaluations were conducted without adding any stabilizer to the black pellets used in Examples 7 to 9. The results are shown in Table-2.

Cracks were found on the surface of the test piece after the environmental test.

Examples 10 to 12 A brown pellet colored with a coloring agent containing iron oxide pigment as the main component was added to the polyester elastomer used in Example 1, and the stabilizer used in Examples 1 to 3 was added to the same. We conducted an evaluation. The results are shown in Table-2.

Comparative Example 8 Similar evaluations were performed on the brown pellets used in Examples 10 to 12 without adding any stabilizer.

The results are shown in Table-2.

There were cracks in the appearance of the test piece after the environmental test.

It can be seen that even when a color pellet is used, the use of the stabilizer having a specific structure of the present invention is effective in preventing deterioration of physical properties after an environmental test.

Evaluation Method Environmental Stimulus Conditions A punched test piece was placed in a No. 3 dumbbell compliant with JIS K6301 at 83°C (18 minute rain cycle in 120 minutes) in a sunshine weather meter tester for 96 hours.
Provided environmental stimulation.

Test method After the above environmental test, according to JIS K6301,
The test piece was subjected to a tensile test, and the tensile strength (T) and elongation at break (E
The retention rate (%) of B) was determined.

Further, the color difference change ΔE (%) of the test piece after the test was measured using a color difference meter to determine the color change after the test.

The following margins [Effects of the Invention] The polyester thermoplastic elastomer composition comprising a polyether ester block copolymer obtained by adding a hindered phenol compound with a specific structure, a benzotriazole compound, and a hindered amine compound of the present invention has a conventional stable composition. Compared to a composition consisting of a combination of agents, a molded article with a higher retention rate of mechanical properties after an environmental test and a smaller change in color of the molded article can be obtained.

Because the composition of the present invention has excellent heat resistance, light resistance, and weather resistance, it can be used in automobile parts such as boots, side moldings, steering rod covers, industrial parts such as hydraulic hoses, tubes, cups, pulls, and conveyors. It can be suitably used for belts, springs, electrical/communication parts, such as telephone curl cords, timing belts, antenna covers, and the like.

Patent applicant: Japan Synthetic Rubber Co., Ltd.

Claims (1)

[Claims] (1) For polyether ester block copolymers, (A) It has a center of symmetry structure, and there are ▲ mathematical formulas, chemical formulas, tables, etc. in the molecule ▼ (In the formula, R and R' have 1 to 1 carbon atoms) 12 hydrocarbon groups, at least one of R and R' is a hydrocarbon group having 4 to 12 carbon atoms, and n = an integer of 0 to 3) having 2 to 4 hindered phenol groups. A thermoplastic elastomer composition comprising a phenol compound (B) a benzotriazole compound having no substituent on the benzotriazole ring, and (C) a stabilizer consisting of a hindered amine compound.