JPH0741626A - Poly(vinyl chloride) resin composition and packing material - Google Patents

Abstract

PURPOSE:To obtain the title resin composition which comprises a poly(vinyl chloride) resin as a matrix and a polyurethane as a dispersion phase and is useful as a packing material because of its excellent compression set. CONSTITUTION:The objective composition has a phase-separation structure comprising (A) a poly(vinyl chloride) resin as a matrix and (B) a polyurethane as a dispersion phase where the tensile modulus of the component A is 9X10<5> to 8X10<7>dyne/cm<2> at 20 to 70 deg.C in the measurement of dynamic viscoelasticity and the ratio of compression modulus of the matrix phase to that of the dispersion phase is 0.4 to 1.8 at 70 deg.C.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a composite resin composition comprising polyurethane, a polyvinyl chloride resin and a plasticizer.

[0002]

2. Description of the Related Art Conventionally, benzoyl peroxide, dicumyl peroxide, and t have been known as methods for improving the load-bearing deformability of polyvinyl chloride resins, that is, the compression set.
-Polymers such as organic peroxides such as butyl peroxide, diamine compounds such as 1,4-tetramethylenediamine and 1,6-hexamethylenediamine, and sulfur compounds such as sulfur, tetramethylthiuram disulfide and triazinedithiol Method by cross-linking vinyl chloride resin,
A method by cross-linking components such as diallyl phthalate, cross-linkable polyurethane or epoxy resin, and further, cross-linked polyvinyl chloride resin which has been cross-linked at the time of polymerization in advance or cross-linked NBR having good compatibility with polyvinyl chloride resin is blended with polyvinyl chloride resin. And a method in which a polyvinyl chloride-based resin having a reactive group such as a hydroxyl group is used to form a crosslinked product with diisocyanate or the like.

In these methods, when a polyvinyl chloride resin is cross-linked, it is possible to easily obtain a composition having a good compression set, but on the other hand, the problem is that the obtained composition melts. The viscosity was remarkably increased, resulting in a material having poor moldability. In addition, (1) poor thermal stability and easy to be colored, (2) odor remains due to the residue of the cross-linking agent, and (3) if the degree of cross-linking is increased, a large amount of plasticizer is used to obtain a predetermined hardness. , Etc.

Further, among the above-mentioned methods, the method involving component cross-linking often causes the same problem as described above because this reaction is often based on a radical reaction system.

Crosslinked polyvinyl chloride resin or crosslinked NBR
When blending etc. with polyvinyl chloride resin,
(1) The physical properties such as tensile strength and elongation are remarkably lowered in relation to their dispersibility in the polyvinyl chloride resin.
(2) A large amount of plasticizer is required for adjusting hardness, (3)
(4) Crosslinked NBR, which deteriorates moldability when added in a large amount
Due to the butadiene component therein, there are problems such as poor weather resistance and poor heat aging resistance.

Further, the method of using a polyvinyl chloride resin having a reactive group such as a hydroxyl group to form a crosslinked product with a diisocyanate or the like has poor reactivity and thus has little improvement effect.

Therefore, in recent years, attention has been paid to a composite of a polyvinyl chloride resin and polyurethane, and various methods have been proposed. For example, polyurethane is a vinyl chloride monomer (V
CM) to obtain a complex of polyvinyl chloride resin and polyurethane by polymerizing VCM, and producing a hydroxyl group-containing polyvinyl chloride resin by polymerizing VCM in the presence of a polyol. There are ways to get it.

However, the composites of polyvinyl chloride resin and polyurethane obtained by these methods are inferior in rubber elasticity and are not suitable for applications requiring these characteristics.

On the other hand, as the packing material, a material excellent in molding workability and compression set is desired from the viewpoint of improving airtightness and the like.

[0010]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a thermoplastic elastomer that maintains moldability and is excellent in compression set.

[0011]

In view of the above-mentioned situation, the present inventors have found that the matrix of the composite of polyvinyl chloride resin and polyurethane is polyvinyl chloride resin,
The present invention has been completed as a result of extensive studies on a phase separation material in which the dispersed phase is polyurethane.

That is, the present invention is a resin composition comprising a polyvinyl chloride resin, a crosslinked polyurethane and a plasticizer, wherein the matrix has a polyvinyl chloride resin and the dispersed phase has a phase separation structure of polyurethane. And the tensile elastic modulus in the dynamic viscoelasticity measurement of the polyurethane used is in the range of 20 ° C. or higher and 70 ° C. or lower, 9 × 10 ⁵ dy
ne / cm ² or more and 8 × 10 ⁷ dyne / cm ² or less, and the ratio of the compression elastic modulus of the matrix phase to the compression elastic modulus of the dispersed phase at 70 ° C. is 0.4 or more and 1.8 or less. And a packing material comprising the present resin composition.

The details of the present invention will be described below.

The polyvinyl chloride resin used in the present invention is a homopolymer of vinyl chloride, a chlorinated vinyl chloride resin, or one or more monomers selected from all monomers copolymerizable with vinyl chloride monomer. Vinyl chloride copolymer resin (for example, vinyl acetate-vinyl chloride copolymer, ethylene-vinyl chloride copolymer, etc.) obtained by random copolymerization or block copolymerization with a monomer, and a functional group such as a hydroxyl group in the above resin. The resin obtained by grafting or a resin obtained by reacting such a functional group with a reactive compound and graft-bonded is a single product or a mixture of two or more kinds of these resins.

The polyvinyl chloride resin may have any degree of polymerization, but from the viewpoint of moldability, one having a polymerization degree of 400 to 8000 is preferably used, and more preferably 500 to 5
000 or less. Further, a polyvinyl chloride resin having a polymerization degree in the above range and a polyvinyl chloride resin having an arbitrary molecular weight may be blended.

The resin composition of the present invention has a phase separation structure in which the matrix is a polyvinyl chloride resin and the dispersed phase is a crosslinked polyurethane. This state can be confirmed by, for example, performing a transmission electron microscope observation (hereinafter referred to as TEM). If the phase-separated structure is not confirmed by TEM, it indicates that the cross-linked structure of polyurethane has spread throughout the system, and the moldability of the obtained resin composition is poor. In addition, osninic acid is used for dyeing at the time of TEM observation.

As a method for obtaining such a phase-separated structure, for example, (1) a method in which polyurethane obtained by previously reacting a polyol with an isocyanate compound is finely crushed by mechanical crushing or the like is mixed into a polyvinyl chloride resin, 2) Among the methods of melt-kneading a polyvinyl chloride resin, a polyol, an isocyanate compound and a plasticizer at the same time to carry out a urethane reaction, a method in which the compatibility between the polyol and the polyvinyl chloride resin is not excellent is used, (3 ) As in the case of (2), among the methods of melt-kneading by heating and carrying out urethane reaction, a method of preferentially causing the polyurethane reaction over the melt gelation of the polyvinyl chloride resin,
However, any method may be used to obtain the phase-separated structure.

In the resin composition of the present invention, the plasticizer is present in both the matrix and the dispersed phase. That is,
Strictly speaking, the resin composition of the present invention has a matrix composed of a polyvinyl chloride resin and a plasticizer, and a dispersed phase composed of a crosslinked polyurethane and a plasticizer.

The polyurethane used in the present invention is a cross-linkable polyurethane obtained from an isocyanate compound and a polymer polyol, at least one of which contains a polyfunctional component having a functionality of 3 or more, and is generally a compression set of a polyvinyl chloride resin. The stress-strain curve in the compression test must be almost the same as that of the polyvinyl chloride resin that serves as the matrix at 70 ° C., which is the temperature at which is measured. Specifically, the ratio of the compressive elastic modulus of the matrix phase to the compressive elastic modulus of the dispersed phase obtained from the slope of the stress-strain curve is 0.4 or more and 1.8 or less, preferably 0.6 or more and 1.5 or less. , And more preferably 0.8 or more and 1.2 or less. If this ratio is less than 0.4 or exceeds 1.8, the compression set characteristics of the resulting resin composition deteriorate.

The method for making the elastic moduli of the matrix and the dispersed phase close to each other is, for example, (1) the molecular weight of the polymer-polyol, the number of functional groups of the polymer polyol or the isocyanate compound, the method of operating the isocyanate index, and (2) the plasticizer. There are various methods such as a method of operating the addition amount.

In the present invention, the blending amount of polyurethane is preferably 30 parts by weight or more, and more preferably 50 parts by weight or more based on 100 parts by weight of the polyvinyl chloride resin. Three
If the amount is less than 0 parts by weight, the effect of improving the compression set of the obtained resin composition may be poor. From the viewpoint of cost performance and molding processability, the amount of polyurethane added is 90 per 100 parts by weight of polyvinyl chloride resin.
The amount is preferably 0 parts by weight or less, more preferably 600 parts by weight or less. If it exceeds 900 parts by weight, the moldability of the obtained resin composition may be significantly deteriorated.

Further, the polymer polyol used for obtaining the polyurethane is not particularly limited. One or more of polyester polyol, polyether polyol, polycaprolactone polyol, polycarbonate polyol, castor oil-based polyol, saponified EVA (ethylene-vinyl acetate copolymer) and the like are used. The polyester polyols shown here include, for example, ether ester type polyester polyols obtained by condensation polymerization of diethylene glycol and adipic acid, and also polyester polyols polyfunctionalized with trimethylolpropane or the like. Further, the polyether polyol, the polycarbonate polyol, and the polycaprolactone polyol also include a polyfunctional polyol having three or more hydroxyl groups.

On the other hand, the isocyanate compound used for obtaining the polyurethane is not particularly limited. For example, 2,4- and 2,6-tolylene diisocyanate, m- and p-phenylene diisocyanate, 1-
Chlorophenylene-2,4-diisocyanate, 1,5
-Naphthalene diisocyanate, methylene bis phenylene 4,4'-diisocyanate, m- and p-xylene diisocyanate, hexamethylene diisocyanate, lysine diisocyanate, 4,4'-methylene biscyclohexyl diisocyanate, isophorone diisocyanate, trimethyl hexamethylene diisocyanate, etc. Triisocyanates such as trimer of diisocyanate, 1,6,11-undecane triisocyanate, lysine ester triisocyanate, 4-isocyanate methyl-1,8-octamethyl diisocyanate, or polyfunctional isocyanates such as polyphenylmethane polyisocyanate And one or more of these are used. It is also possible to use the above diisocyanates together.

Further, the polyurethane used in the present invention has a tensile elastic modulus of 20 ° C. or more and 70 ° C. in linear viscoelasticity measurement.
9 × 10 ⁵ dyne / cm ² or more 8 × in the following range
10 ⁷ dyne / cm ² or less, more preferably 1 × 10 ⁶
It is desirable to use polyurethane having a dyne / cm ² or more and 7 × 10 ⁷ dyne / cm ² or less. When manipulating to make the elastic moduli of the dispersed phase and the matrix equal,
If the elastic modulus of the polyurethane that is the dispersed phase is too low, a large amount of plasticizer is required for the polyvinyl chloride resin that is the matrix, and bleedout easily occurs.If the elastic modulus of the polyurethane is too high, the matrix also becomes hard. ,
This is because the flexible nature is lost.

As described above, the material in which the polyvinyl chloride resin and the polyurethane are phase-separated in the blend of the polyvinyl chloride resin and the crosslinked polyurethane has excellent compression set characteristics due to the rubber-like properties of the crosslinked polyurethane. . The mechanism for improving the compression set by the crosslinked polyurethane will be described.

When the compression set is improved by the crosslinked polyurethane, the driving force for improving the compression set is derived from the strain energy of the crosslinked polyurethane immediately before the strain is released. This strain energy is defined as 1/2 of the product of the square of the strain and the elastic modulus, and the larger the strain energy, the greater the effect of improving the compression set.

That is, in order to improve the compression set, two conditions are required: (1) increase the strain and (2) increase the elastic modulus of the crosslinked polyurethane immediately before releasing the strain. However, when the elastic modulus of the disperse phase spreads around the matrix, the disperse phase is less likely to be deformed when the initial strain is applied, and the strain becomes small. Therefore, it is considered that when the strain is released, the strain energy of the dispersed phase becomes maximum when the elastic moduli of the matrix and the dispersed phase are equal, and at this time, the effect of improving the compression set is greatest.

Examples of the plasticizer which can be used in the present invention include di-n-butyl phthalate, di-2-ethylhexyl phthalate (DOP), di-n-octyl phthalate and diisodecyl phthalate. , Phthalic acid-based plasticizers such as diisooctyl phthalate, octyldecyl phthalate, butylbenzyl phthalate and di-2-ethylhexyl isophthalate, di-2-ethylhexyl adipate (DOA), di-n-decyl adipate, adipine Acid diisodecyl, dibutyl sebacate, di-sebacate
Aliphatic ester plasticizer such as 2-ethylhexyl, trioctyl trimellitate, pyromellitic acid plasticizer such as tridecyl trimellitate, tributyl phosphate, tri-2-ethylhexyl phosphate, 2-ethylhexyl diphenyl phosphate, phosphorus Phosphate ester plasticizers such as tricresyl acid acid, epoxy plasticizers such as epoxy soybean oil,
Chlorinated paraffin, polymer plasticizers typified by polyester polymer plasticizers, high molecular weight compounds having a glass transition temperature lower than that of polyvinyl chloride resins and having plasticizing ability for polyvinyl chloride resins, etc. And one or more of these can be used. And the above plasticizer is appropriately selected according to the purpose, for example, heat resistance, a high molecular weight plasticizer may be used to improve non-migration, and dibutyldiglycol adipate or the like may be used to improve oil resistance. Good. Further, in order to improve the fluidity, it is advisable to add an adipic acid ester plasticizer or a sebacic acid ester plasticizer.

The addition amount of the plasticizer is polyvinyl chloride resin 1
It is preferably 10 parts by weight or more and 200 parts by weight or less, more preferably 25 parts by weight or more and 1 part by weight with respect to 00 parts by weight.
It is 50 parts by weight or less. If it is less than 10 parts by weight, moldability may be impaired, and if it exceeds 200 parts by weight, bleed-out may occur.

The polyvinyl chloride resin composition of the present invention contains an inorganic filler such as calcium carbonate or talc, which is usually added to the polyvinyl chloride resin to the extent that the performance thereof is not extremely deteriorated, and trioxide. Flame retardants typified by antimony and zinc borate, modifiers such as partially crosslinked polyvinyl chloride and partially crosslinked acrylonitrile-butadiene rubber (NBR), processing aids typified by acrylic resins, metal salts, hydrotalcite. A heat stabilizer represented by, for example, can be added if necessary. In addition, when other resin is added, it is possible to use a compatibilizing agent of the present resin composition and the other resin together as the third component.

[0031]

EXAMPLES The present invention will be described below with reference to examples.
The present invention is not limited to these examples.

The compression set measuring method in accordance with JIS K6301 in the examples is as follows. A test piece is inserted into a test die set at 70 ° C. in advance, a strain of 25% is applied, and then 22 hours have passed. After that, the strain is released, and the sample is left at room temperature for 30 minutes, and the change in the sample thickness before and after the test is measured.

Example 1 Polyester polyol obtained by condensation polymerization of 3-methyl-1,5-pentanediol and adipic acid (manufactured by K.K.)
Kuraray Co., Ltd., trade name CLAPOL P4010, number average molecular weight 4000) 100 parts by weight and an isocyanurate modified product of hexamethylene diisocyanate as an isocyanate compound (polyfunctional isocyanate compound, average number of functional groups: 3.6 / molecule) (Nippon Polyurethane Co., Ltd., trade name Coronate HX) 10 parts by weight (NCO / OH (isocyanate index) = 1.0), and DBTDL (dibutyltin dilaurate) 26.7PP as a catalyst.
M was mixed and left in an oven at 120 ° C. for 2 hours to prepare polyurethane. 0.5 thickness from this sample
A strip-shaped test piece having a size of 5 mm, a width of 5 mm, and a length of 25 mm was cut out to obtain a test piece for measuring the dynamic viscoelasticity of polyurethane.
Separately, polyurethane was finely crushed with a roll molding machine having a surface temperature of 150 ° C. to prepare a sample for blending.
In addition, polyvinyl chloride resin (Shin-Etsu high degree of polymerization PVC T
K-2500W, average degree of polymerization: 4500, manufactured by Shin-Etsu Chemical Co., Ltd., 100 g, 2 g of barium stearate as a stabilizer, 1 g of zinc stearate, amine scavenger (trade name BP-331 manufactured by Nissan Ferro Organic Chemical Co., Ltd.) ) 1.5 g,
100 g of di-2 ethylhexyl phthalate (DOP),
100 g of finely crushed polyurethane for blending was thoroughly mixed at room temperature, and then kneaded by a roll forming machine set to a surface temperature of 150 ° C. The kneading time was 15 minutes. The composite thus obtained was press-molded to have a thickness of 12.70 ± 0.13 mm for JISK6301 compression set.

Further, the uneven distribution amount of DOP in the matrix and the dispersed phase was obtained according to the method separately described in <Measurement of uneven distribution of plasticizer>. A mixture of polyvinyl chloride resin and DOP corresponding to the matrix is mixed by a roll forming machine based on the uneven distribution amount obtained here, so that the thickness becomes 12.70 ± 0.13 mm for JISK6301 compression set measurement. Then, it was press molded. In addition, polyurethane and DO corresponding to the dispersed phase
Polymer polyol, isocyanate compound, DOP, DBTDL26.7 as a catalyst for the purpose of obtaining a mixture of P
PPM was thoroughly mixed, poured into a mold having a depth of 12.70 ± 0.13 mm, and allowed to stand in an oven at 120 ° C. for 2 hours to obtain a material corresponding to a dispersed phase. The types and grades of raw materials used were all those listed in this example.

The composite material corresponding to the matrix and the composite material equivalent to the dispersed phase were respectively compressed at a compression speed of 0.2 at 70 ° C.
A compression test was performed at mm / min, and a stress-strain test was performed.
The elastic modulus of each material was obtained from the initial gradient of the stress-strain curve.

<Measurement of uneven distribution of plasticizer> DOP as a plasticizer was blended with 10 parts by weight, 20 parts by weight, 30 parts by weight, 40 parts by weight and 50 parts by weight with respect to 100 parts by weight of polyurethane, respectively. It was poured into a 1 mm thick mold and cured by heating to form a sheet, which was used as a sample for migration test. Polyvinyl chloride resin 100
DOP 50 parts by weight, 60 parts by weight, 7 parts by weight
Stabilizer was further added to 0 parts by weight, 80 parts by weight, and further 90 parts by weight, kneaded sufficiently by a roll kneader, and made into a 1 mm thick sheet by a press molding machine, and used as a sample for migration test. did.

For the purpose of obtaining information on the uneven distribution of DOP in the dispersed phase and the matrix, 10 parts by weight of D was added to polyurethane.
90% for samples with OP added and polyvinyl chloride resin
Part by weight DOP is added and the sample is pasted to 70 ℃
A migration test was conducted at. Similarly, a sample of 20 parts by weight of DOP for polyurethane and a sample of 80 parts by weight of DOP for polyvinyl chloride resin, a sample of 30 parts by weight of DOP for polyurethane and a sample of 70 parts by weight of DOP for polyvinyl chloride resin, A sample of 40 parts by weight of DOP for polyurethane and a sample of 60 parts by weight of DOP for polyvinyl chloride resin, and a sample of 50 parts by weight of DOP for polyurethane and a sample of 50 parts by weight of DOP for polyvinyl chloride resin, Were bonded to each other and a migration test was performed at 70 ° C. The test time was 24 hours. The transferability is evaluated by the weight change rate, and the DOP with the smallest weight change rate is obtained.
To the matrix and disperse phase in equilibrium
It was determined as the uneven distribution of P.

Comparative Example 1 Instead of the polyester polyol used in Example 1, 100 parts by weight of a polyester polyol having the same composition and a number average molecular weight of 500 (Kuraray Co., Ltd., trade name CLAPOL P510) and an isocyanate compound were used. 7
A composite material was obtained by the same operation as in Example 1 except that 9.8 parts by weight (NCO / OH = 1.0) was used.

Comparative Example 2 In place of the polyester polyol used in Example 1, 100 parts by weight of a polyester polyol having the same composition and a number average molecular weight of 6000 (Kuraray Co., Ltd., trade name CLAPOL P6010) and an isocyanate compound were used. A composite material was obtained by the same operation as in Example 1 except that 6.0 parts by weight (NCO / OH = 0.9) was used.

The material obtained as described above was subjected to the evaluation test described below. The results are shown in Table 1.

(Measurement of compression set) The compression set was measured according to JIS K6301. The initial strain was 25%, the temperature was 70 ° C., the strain was released after 22 hours, and the residual strain was measured.

(Measurement of compressive elastic modulus) A compression test was carried out in a Tensilon tensile tester. Test temperature is 70 ℃,
The compression speed was 0.2 mm / min.

(Measurement of Tensile Elastic Modulus) Viscoelasticity Analyzer R which is a measuring device based on the non-resonance type forced vibration method.
The tensile storage elastic modulus (E ′) at 23 ° C. was measured by using SAII (Rheometrics Far East Co., Ltd.) at a measurement frequency of 10 Hz and a measurement mode: tension. All measurements were performed in the linear region.

(Confirmation of phase structure) The obtained composite material was Os.
It is exposed to a vapor of O ₄ and dyed, and then it is made into an ultrathin section of 0.1 micron in an atmosphere of -100 ° C with an ultramicrotome. This is an electron microscope DEOL JEM-20
It was observed at an acceleration voltage of 200 kV using 00FX. Upon this observation, it was confirmed that the polyurethane component dyed with OsO ₄ was a dispersed phase superior in size of 0.1 to 100 microns.

[0045]

[Table 1]

[0046]

As described above, the resin composition of the present invention becomes a thermoplastic elastomer excellent in compression set.

Claims (2)

[Claims] 1. A resin composition comprising a polyvinyl chloride resin, a crosslinked polyurethane and a plasticizer, wherein the matrix has a polyvinyl chloride resin and the dispersed phase has a phase separation structure of polyurethane. The tensile modulus of elasticity of the polyurethane used in the dynamic viscoelasticity measurement is 20 ° C. or higher 70
9 × 10 ⁵ dyne / cm ² or more in the range of ℃ or less 8
A thermoplastic elastomer resin having a density of × 10 ⁷ dyne / cm ² or less and a ratio of the compression elastic modulus of the matrix phase to the compression elastic modulus of the dispersed phase at 70 ° C. of 0.4 or more and 1.8 or less. Composition. 2. A packing material comprising the thermoplastic elastomer resin composition according to claim 1.