JPH04348151A - Non-rigid vinyl chloride resin composition - Google Patents

Abstract

PURPOSE:To obtain a non-rigid vinyl chloride resin composition having a wide temperature range of practical use, excellent heat resistance, freeze resistance and long-term durability. CONSTITUTION:(A) 100 pts.wt. vinyl chloride resin having 700-2,500 average polymerization degree is blended with (B) 20-150 pts.wt. aliphatic thermoplastic polyurethane and (C) 60-150 pts.wt. compd. alkyl phthalic ester having a chemical structural formula shown by the formula (m and n are 7-9).

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention has a wide practical temperature range.
This invention relates to a soft vinyl chloride resin composition that has excellent heat resistance, cold resistance, and long-term durability.

0002

[Prior Art] Conventionally, softened vinyl chloride resin has been widely used for automotive parts such as steering wheel pads and assist grips, hoses, films, leather, gaskets, and wire covering materials because of its toughness and excellent soft flammability. ing. Among the above automobile parts, for example, soft vinyl chloride resin for steering wheel pads is required to be a material with excellent heat resistance, migration resistance, and low volatility. On the other hand, recently, from the perspective of improving safety, energy absorption mechanisms and air bag mechanisms have been adopted in new specifications of steering wheel pads, and there is a need for steering wheel pads to be highly flexible without becoming brittle even in low-temperature regions. Ru. In other words, in addition to the characteristics that soft vinyl chloride resin has conventionally possessed, the above-mentioned member has the characteristics that soft vinyl chloride resin has conventionally.
It is also required to have flexibility in the vicinity.

Mixing a plasticizer is a method for improving the low-temperature properties of vinyl chloride resin, and it is known that the glass transition point (Tg) can be freely controlled by changing the type and amount of plasticizer mixed. However, in order to impart low-temperature flexibility even at -40°C, it is necessary to mix a large amount of plasticizer, which causes problems such as surface stickiness, heat resistance, and plasticizer bleed/volatility. As a method to solve these problems, it is known to replace part or all of the plasticity with thermoplastic elastomer, which has excellent cold resistance.Among these, thermoplastic polyurethane resin is mixed in because of its compatibility with vinyl chloride resin. Many proposals have been made (Unexamined Japanese Patent Publication No. 5
5-116747, 52-108454, 53-186
56, 60-92345).

[0004] However, even in these methods,
Effect of improving cold resistance, cold resistance and heat resistance, volatility resistance,
The balance with bleed resistance is still insufficient, and a material with a wide practical temperature range and excellent heat and cold resistance has not yet been found. In view of these points, the applicant has previously proposed a soft vinyl chloride resin in which thermoplastic polyurethane and a sebacic acid plasticizer are mixed in specific proportions with vinyl chloride resin (Japanese Patent Application No. 1-279455). ).

[0005]

[Problems to be Solved] However, the above-mentioned soft vinyl chloride resin has the following problems. That is, the soft vinyl chloride resin of the above application has t, which is a measure of the glass transition temperature (Tg).
When the peak temperature of the an δ main dispersion is -15°C or lower, no embrittlement of the material is observed even at -40°C, and the tensile modulus at high temperatures is high. Therefore, compared to conventional soft vinyl chloride resins, it has excellent physical properties such as flexibility and elastic modulus, especially in the low temperature range of -40°C to the high temperature range of 100°C. However, because this resin has a large volatilization loss during heat aging, it cannot be applied to functional parts such as steering wheel pads with the new specifications mentioned above, which have strict requirements for durability and heat resistance. The present invention has been made in view of the above-mentioned problems.
The object of the present invention is to provide a soft vinyl chloride resin composition that is flexible in the practical temperature range of °C and has excellent long-term durability such as heat resistance, heat aging resistance, and light resistance.

[0006]

[Means for solving the problems] The present invention consists of 100 parts by weight of vinyl chloride resin and 20 to 150 parts by weight of aliphatic thermoplastic polyurethane.
parts by weight, and a composite alkyl phthalate ester having the following chemical structural formula (in the chemical structural formula, m and n are 7 to 9) 60 to
150 parts by weight of the soft vinyl chloride resin composition.

[Chemical formula 1]

[0007] In the present invention, the vinyl chloride resin is
A material having an average degree of polymerization of, for example, 700 to 2,500 is used. When the average degree of polymerization is less than 700, kneading properties,
It has poor dispersibility and causes flow marks during molding. On the other hand, when the average degree of polymerization exceeds 2500, the moldability deteriorates,
Shrinkage of the molded product increases after molding. Further, as the above-mentioned vinyl chloride resin, it is also possible to use a crosslinked resin and a low polymerization degree resin in combination. Further, the vinyl chloride resin preferably has an average degree of polymerization of 1000 or more. In this case, kneadability, dispersibility, etc. will be better.

[0008] As the thermoplastic polyurethane, one made of, for example, an ester type polyol and an aliphatic isocyanate is used. Specific raw materials include adipic acid, 1,4-butanediol,
There is a combination with hexamethylene diisocyanate. The thermoplastic polyurethane is blended in an amount of 20 to 150 parts by weight with respect to 100 parts by weight of the vinyl chloride resin. If the amount is less than 20 parts by weight, the peak temperature of the tan δ main dispersion will not shift sufficiently. On the other hand, if it exceeds 150 parts by weight, the amount of plasticizer increases to adjust the hardness, and as a result, the difference in viscosity between the vinyl chloride resin and the thermoplastic polyurethane increases. Therefore, the dispersibility of thermoplastic polyurethane deteriorates.

[0009] The composite alkyl phthalate ester (hereinafter referred to as composite APE) is a plasticizer, has the chemical structural formula described above, and has m and n of 7 to 9. m above
, n is 7, dihectyl phthalate, m, n is 8
The one is dioctyl phthalate. Also, m and n are 1
A content of 0 or more causes light-resistant blades when added in a large amount, which is undesirable. It is preferable that the linear chain ratio (normal type) of the ester portion of the composite APE is 80% or more. The plasticizer is blended in an amount of 60 to 150 parts by weight with respect to 100 parts by weight of the vinyl chloride resin. If the amount is less than 60 parts by weight, the molded product will have high hardness and poor flexibility. On the other hand, if it exceeds 150 parts by weight, the hardness of the molded product will decrease and bleed will occur, making it impractical.

Note that a filler can be added to the above composition. Such fillers are preferably plate-shaped materials such as talc, mica (mica) calcined clay, and kaolin clay. This improves heat resistance and prevents the molded product from deforming at high temperatures. The feeler is
For example, 10 to 100 parts by weight of the above vinyl chloride resin
100 parts by weight is blended. If the amount is less than 10 parts by weight, the mechanical strength such as the elastic modulus of the molded product will decrease, and the shrinkage after molding will increase. On the other hand, if it exceeds 100 parts by weight, physical properties such as tensile strength and elongation of the molded article will decrease, and moldability will also deteriorate.

[0011]

[Operations and Effects] In the soft vinyl chloride resin composition of the present invention, by mixing a specific amount of thermoplastic polyurethane with a specific soft vinyl chloride resin, the thermoplastic polyurethane is uniformly dispersed, and the soft vinyl chloride resin is The mechanical strength of thermoplastic polyurethane, such as toughness and elasticity, and excellent cold resistance are effectively added to the mechanical strength unique to resin. As a result, the tan δ peak temperature of this composition decreased to below -10°C, and the material maintained its softness even at -40°C, and the elastic modulus could be maintained above a certain value even at high temperatures (100°C). It has been discovered that it has properties that cannot be obtained with conventional soft vinyl chloride resin. Furthermore, since the present invention uses aliphatic thermoplastic polyurethane, it does not discolor due to irradiation with heat or light.

Furthermore, in the present invention, a synergistic effect can be obtained in the balance between cold resistance (glass transition temperature) and heat resistance (elastic modulus at high temperatures) by using the thermoplastic polyurethane and a specific plasticizer together. can. That is, cold resistance and heat resistance are generally contradictory properties, and there is a negative correlation in that heat resistance decreases as cold resistance improves. This relationship can be considerably improved by mixing thermoplastic polyurethane with the soft vinyl chloride resin as described above. However, especially as a plasticizer, the linearity is 80~80~
When 100% composite alkyl phthalate ester is applied, this balanced property is extremely excellent, and a composition having cold resistance and heat resistance that could not be expected using conventional techniques can be obtained.

Furthermore, m, which indicates the molecular weight of the plasticizer,
When n is 7 to 9, it is possible to obtain a composition that has extremely excellent long-term durability performance such as heat aging resistance and light resistance in addition to the balanced characteristics of cold resistance and heat resistance. The reason why a synergistic effect is obtained in the relationship between cold resistance and heat resistance in this composition is thought to be related to the mutual compatibility of the vinyl chloride resin, plasticizer, and thermoplastic polyurethane resin. That is, it is expected that the plasticizer is mainly absorbed into the vinyl chloride resin side, and that the thermoplastic polyurethane is mixed into a homogeneous mixture of vinyl chloride resin/plasticizer. However, although the exact reason is not clear, when the above plasticizer is used, the compatibility between the homogeneous mixture of vinyl chloride resin/plasticizer and thermoplastic polyurethane is optimal, and the thermoplastic polyurethane is mixed extremely uniformly. It is also presumed that this is due to fine dispersion. As described above, according to the present invention, a soft vinyl chloride resin composition having excellent cold resistance, heat resistance, and long-term durability can be provided. As described above, according to the present invention, it is possible to provide a flexible vinyl chloride resin composition that can be used even in places with large environmental temperature differences (for example, -40°C to 100°C) and has excellent heat resistance and cold resistance. .

[0014]

[Examples] Examples according to the present invention and comparative examples will be explained below. Mixing ratio of ingredients in each example (parts by weight)
, as well as the hardness and tensile strength of various compositions at room temperature,
The measurement results of tensile elongation, tan δ peak temperature (measure of glass transition point Tg), tensile modulus at 100°C (dyne value per 1 cm2), light resistance, and heat resistance are shown in Tables 1-
It is shown in Table 4.

[0015] The measured values of the tensile modulus and the like are the average values of the values obtained by preparing test pieces (2 x 5 x 50 mm) and measuring several times. Moreover, the light resistance is the result of irradiation at 83° C. for 400 hours as a condition for a fade test. Also,
Heat resistance is the result of visual inspection after treatment at 80° C. for 500 hours. In Tables 1 to 4, PVC is vinyl chloride resin and TPU is thermoplastic polyurethane. First, in all Examples except Examples 11 and 12, PVC with an average degree of polymerization of 1300 was used, and PVC
All amounts of 100 parts by weight were blended. On the other hand, in the comparative example as well, the PVC was the same as in the example.

Regarding the blending amount of thermoplastic polyurethane, 50 parts by weight of an aliphatic polyurethane was blended in all cases other than Examples 1 to 6. On the other hand, in the comparative example, C3 and C5
50 parts by weight of the other ingredients were added. C3 does not contain the above thermoplastic polyurethane. Also, C1, C2, C4,
Aliphatic TPU was used for C7, C8, C9, and C10. Further, for C6, an aromatic TPU with a polyol component of ether was used. For C5, a simple aliphatic polyurethane was used. Regarding plasticizers, n-DOP (normal dioctyl phthalate, m, n = 8 in the above chemical structure, manufactured by Kao Corporation), or the product name Lineball Phthalate (m, n = 7 in the above chemical structure)
~9, PL100 (manufactured by Mitsubishi Gas Chemical Co., Ltd.) was used. In addition, in comparative example C4, lineball phthalate (m, n
=9~11, PL200) (manufactured by the same company), C1
In this case, DOP (manufactured by Toho Rika Co., Ltd.) was used. Also,
In Comparative Example C2, DBS (manufactured by Sanken Kako Co., Ltd.) was used. For C-7, DOA (manufactured by Toho Rika Co., Ltd.) was used. C8 is lineball phthalate (the above m, n = 1
0 to 14, RH100, manufactured by the same company). For C9, DIDP (manufactured by the same company) was used. Also, C10
In this case, DNDP (manufactured by Kao Corporation) was used. Also, C5
does not use plasticizers.

[0017] The thermoplastic polyurethane having the above composition was obtained by heating pellets after polymerization and then pelletizing them again. The above heating treatment is 180~2
It refers to heat treatment using an extruder or the like at 00°C. As a result,
The thermoplastic polyurethane becomes transparent, and the kneading processability with the soft vinyl chloride resin is improved. Next, the above measurement results will be explained. Regarding hardness, see Tables 1 and 2.
As is known, all except Example 6 are 66-7.
The hardness was constant at 4 (Hs), indicating suitable hardness. In addition, Example 6 exhibited a slightly high hardness of 80 (Hs).

On the other hand, as can be seen from Table 3, Comparative Example C5 had a value of 92 (Hs), indicating that the soft feel was lost. Next, tanδ, which is a measure of the glass transition point Tg,
Regarding the peak temperature of the main dispersion, Examples 1 to 12 were -
The temperature ranges from 17℃ to -43℃, extending into a fairly low temperature range. In contrast, the tan δ of Comparative Examples C1, C3, and C9
It is known that because the peak temperature of the main dispersion is as high as -10°C or higher, the low-temperature properties are poor and the material becomes brittle. Regarding the tensile modulus at 100°C, all of the examples have a practical strength of 1×107 dyn/
cm2, preferably 1.5×107
It is preferable to maintain an elastic modulus of dyn/cm2 or more.

Regarding light resistance, all of the Examples were good, but bleeding occurred in Comparative Examples C4, C8, and C10, and the light resistance was not excellent. In addition, all of the examples are good in heat resistance. On the other hand, comparative example C1
, C2, and C7 have large volatilization loss of plasticizer and have problems in practical use. Note that in the table, ○ marks indicate good light resistance and heat resistance, and × marks indicate poor light resistance and heat resistance. Cold resistance (glass transition point) and heat resistance (tensile modulus at 100°C) when the type of plasticizer is changed in a compound system in which the degree of polymerization of vinyl chloride resin is 1300 and the amount of thermoplastic polyurethane is 50 parts by weight. ) is shown in Figure 1.

As can be seen from Figure 1, alkyl phthalate esters with a linear chain ratio of 80 to 100% and molecular weight m and n of 7 to 11 as plasticizers have a particularly good balance between cold resistance and heat resistance. It can be seen that when n and m are 7 to 9, the light resistance is also excellent. As described above, according to the present invention, it is possible to obtain a soft vinyl chloride resin composition whose practical temperature range is widened from -40°C or lower to 100°C. Therefore, according to this example, the environmental temperature difference is 140
It is possible to obtain a soft vinyl chloride resin composition that exhibits relatively little change in physical properties in a wide practical temperature range of °C, and has excellent heat resistance, cold resistance, and long-term durability.

[0021]

[Table 1]

[0022]

[Table 2]

[0023]

[Table 3]

[0024]

[Table 4]

[Brief explanation of the drawing]

[Figure 1] Tan δ peak temperature and 100°C in Examples
Graph showing the relationship between tensile modulus in .

[Explanation of symbols]

○． ．． ．． Example, △． ．． ．． Comparative example,

Claims (1)

[Claims] Claim 1: 100 parts by weight of vinyl chloride resin, 20 to 150 parts by weight of aliphatic thermoplastic polyurethane, and a composite alkyl phthalate ester having the following chemical structural formula (in the chemical structural formula, m and n are 7). ~9) A soft vinyl chloride resin composition comprising 60 to 150 parts by weight. [Chemical formula 1]