JPH09302185A - Flexible vinyl chloride resin composition and ptc heating element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a flexible vinyl chloride resin composition which has proper flexibility, high migration resistance and also excellent heat resistance and processability. SOLUTION: This vinyl chloride resin composition comprises (A) 100 pts.wt. of vinyl chloride resin, (B) 50-500 pts.wt. of one or two or more of polymer inner plasticizer selected from the polymer resins: nitrile-butadiene rubber(NBR), acryl rubber, EVA, EEA, chlorinated polyethylene(CPE), (C) 2-15 pts.wt. of one or two or more stabilizers selected from single system stabilizers, for example, Sn, Ba, Zn or a metal soap, binary and ternary system stabilizers Ba-Zn, Ba-Zn-Mg, Ca-Zn, Ca-Zn-Mg or Ca-Zn-Sn system stabilizers, (D) 0.2-5 pts.wt. of one or two or more of antioxidants selected from phenolic, amine or ester antioxidants and (E) 1-5 pts.wt. of one or two or more of lubricants selected from amide resins, acrylic resins and paraffinic lubricants.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a soft vinyl chloride resin-based composition having appropriate softness, high migration resistance, and excellent heat resistance and processability, and a PTC using the same.
It relates to a heating element.

[0002]

2. Description of the Related Art In a vinyl chloride resin or a resin composition containing this as a main component, in order to adjust the hardness,
Generally, a plasticizer such as phthalic acid ester is added. If the added amount of this plasticizer is about 25 to 50%,
It is generally called a soft vinyl chloride resin-based composition, and a plasticizer having an added amount of about 10% or less is called a hard vinyl chloride resin-based composition.

In the case of the above-mentioned soft vinyl chloride resin composition, since it is soft and has appropriate flexibility and is excellent in processability such as extrusion, for example, electric wires and cables,
As an insulating coating for linear or planar PTC heating elements, etc.
Widely used.

[0004]

However, in the above-mentioned conventional soft vinyl chloride resin-based composition, if the added plasticizer easily migrates and is in contact with another resin in the used state,
There is a problem that it adversely affects other resins. Taking the case of a PTC heating element as an example, this heating element is a heating section in which two electrode conductors are embedded in a semiconductive composition obtained by mixing a conductivity-imparting material in a crystalline polymer. Is formed, and an insulating coating is applied to the outer periphery thereof. When the above conventional soft vinyl chloride resin-based composition is used as the insulating coating, the plasticizer in the composition is added to the semiconductive composition side. There was a problem with the transition. When such a plasticizer is transferred, the characteristics (electrical resistance value, etc.) and physical properties of the semiconductive composition are naturally changed, and the original purpose of the PTC heating element cannot be obtained.

Therefore, even in the conventional case, when forming an article requiring low migration, a polyester having a relatively low migration is used instead of the addition of a plasticizer such as phthalate ester having a high migration. A method of adding a system polymer (molecular weight of 1000 or more) as a polymerization type plasticizer has been proposed. However, even with this polymerization type plasticizer, the PT
In the case of something like a C heating element, there is always a thermal stress of temperature change, and load stress is added depending on the place of use (for example, a PTC heating element was laid under a load such as a roof tile for snow melting). However, there is a problem that the migration of the plasticizer and the like is inevitable over time.

Therefore, as another method, NBR is used.
Alternatively, a method of using a polymer material such as EVA or EEA as an internal plasticizer has been partially proposed. In this case, compared to the polymerization type plasticizer such as the polyester resin,
Although the migration resistance is further improved, the above PTC
When considering an application such as a heating element that is extremely reluctant to migrate, it was still insufficient. The reason is that even if NBR, EVA, EEA or the like is simply added as the polymer internal plasticizer, a good combination with other additives such as stabilizers, antioxidants and lubricants is not considered. The reason is that, under severe conditions, the transfer of some contained substances was unavoidable. The same thing can be said about heat resistance, and there is a problem that high heat resistance cannot be obtained by simply adding NBR, EVA, EEA or the like.

Under these circumstances, the present inventors have repeated various tests and studies and as a result, have a high migration resistance even under harsh conditions such as the above-mentioned insulating coating of the PTC heating element. It has been found that the following points should be noted in order to obtain a soft vinyl chloride resin-based composition which has the sufficient heat resistance (for example, about 105 °) and good processability as well as having the above properties. In other words, the soft vinyl chloride resin composition is almost the same as the above-mentioned conventional one in that the polymer internal plasticizer is added, but it has an extremely high migration resistance in applications such as insulation coating of PTC heating elements. When low properties are required, if organic low molecular weight additives are easily used,
It is considered that these additives have a kind of melting point in a certain temperature range and cause migration, so addition of such low-molecular-weight additives takes the position of removing them as much as possible, but it is not suitable for polymerizing polymer materials. Requires a minimum of essential additives such as reaction catalysts, initiators, dispersants, etc., and it is difficult to completely remove them, so other additives used, such as stabilizers, antioxidants, lubricants, etc. After carefully examining the combination with the above and setting it optimally, it was found that even under severe conditions, high migration resistance, heat resistance, workability, etc. were obtained.

[0008] Conventionally, plastic-free vinyl chloride resin materials to which plasticizers have not been added include commercially available products provided by compound makers and the like, for example, substances such as epoxidized soybean oil. Was sometimes added as a stabilizer, and it was also found that this was involved in migration. Therefore, if high migration resistance (absolutely non-migration) is required, whether or not there are such careless additions of additives even in the base vinyl chloride resin material. Turns out to be strict and scrutinized. This is true even in the case of a polymeric internal plasticizer. For example, commercially available high molecular weight internal plasticizers for vinyl chloride resins include a small amount of vinyl chloride resin or a small amount of vinyl chloride resin in advance in order to improve compatibility with the vinyl chloride resin on the material manufacturer side. It was also found that plasticizers and the like were added as a set, which was related to migration.

The present invention has been made from such a point of view, and is a soft vinyl chloride resin composition having high migration resistance and excellent heat resistance and processability, and a PTC using the same. It is intended to provide a heating element.

[0010]

The soft vinyl chloride resin composition according to claim 1 of the present invention comprises a vinyl chloride resin 10
0 parts by weight and nitrile butadiene rubber (NB
R), acrylic rubber, EVA, EEA, chlorinated polyethylene (CPE) polymer resin, 1
Alternatively, 50 to 500 parts by weight of two or more polymer internal plasticizers, Sn-based, Ba-based, Zn-based, metal soap-based independent stabilizers, Ba-Zn-based, Ba-Zn-Mg-based, Ca-Zn
1 or 2 or more stabilizers selected from the group consisting of Ca-Zn-Mg-based and Ca-Zn-Sn-based composite stabilizers 2
15 parts by weight, 0.2 to 5 parts by weight of one or more antioxidants selected from phenol-based, amine-based, or ester-based antioxidants, amide-based, acrylic resin-based, and paraffin-based 1 or 2 selected from among the lubricants
It comprises 1 to 5 parts by weight of the above lubricant.

The soft vinyl chloride resin composition according to claim 2 of the present invention comprises 100 parts by weight of vinyl chloride resin, nitrile butadiene rubber (NBR), acrylic rubber,
50 to 500 parts by weight of one or more polymer internal plasticizers selected from polymer resins of EVA, EEA, and chlorinated polyethylene (CPE), Pb-based single stabilizer, Ba-Zn 2 to 15 parts by weight of one or two or more stabilizers selected from the group consisting of a system + Pb metal soap-based stabilizer, and a phenol-based, amine-based, or ester-based antioxidant. Alternatively, it is composed of 0.2 to 5 parts by weight of 2 or more antioxidants and 1 to 5 parts by weight of 1 or 2 or more lubricants selected from amide-based, acrylic resin-based and paraffin-based lubricants.

The soft vinyl chloride resin composition according to claim 3 of the present invention is the composition according to claim 1 or 2, in which calcium carbonate, talc, barium sulfate, zeolite, clay, or silica is filled. Selected from among the agents,
The composition contains less than 200 parts by weight of one or more fillers.

A PTC heating element according to claim 4 of the present invention is
2. A PTC heating element comprising a semiconductive composition prepared by mixing a conductivity-imparting material in a crystalline polymer, and a heating part formed by embedding two electrode conductors with an insulating coating. ,
A heating element having the soft vinyl chloride resin composition according to 2 or 3 as an insulating coating.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The vinyl chloride resin used in the soft vinyl chloride resin composition of the present invention includes, in addition to the vinyl chloride resin itself, a resin containing a vinyl chloride resin as a main component, that is, ethylene. Includes resins such as vinyl chloride, EVA grafted vinyl chloride. These resins may be used alone or in combination of two or more. Even if it is called a non-plasticized vinyl chloride resin material, in the commercial products provided by compound makers, etc., a substance such as epoxidized soybean oil is added as a stabilizer as described above. Therefore, in the present invention, a substance that does not contain such a substance is carefully selected, or a substance obtained by removing the substance is used.

As the polymer internal plasticizer used in the soft vinyl chloride resin composition of the present invention, nitrile butadiene rubber (NBR), acrylic rubber, E
Polymeric resins such as VA, EEA and chlorinated polyethylene (CPE) may be mentioned, and these may be used alone or in combination of two or more. Also in the case of these resins, in the commercially available products as described above, various substances, vinyl chloride resin or plasticizer for enhancing compatibility, and other trace components may be added in advance. In the present invention, a substance that does not contain such a substance is carefully selected, or a substance that has been appropriately removed is used. By adding this polymeric internal plasticizer, due to the effect of combined use with a lubricant, etc., it can be melted in a homogeneous dispersed state by applying appropriate heating and kneading, and a sea-island structure can be constructed, so it is stable. A flexible structure composition can be obtained. Then, the addition amount is 5 with respect to 100 parts by weight of the vinyl chloride resin.
If the amount is less than 50 parts by weight, the softening effect is not sufficiently obtained, and conversely, if it exceeds 500 parts by weight, gelation of the polymeric internal plasticizer can be controlled. This is because it disappears, the workability and kneading properties are significantly reduced, and continuous production becomes impossible.

Stabilizers used in the soft vinyl chloride resin composition of the present invention include Sn-based, Ba-based and Z-based stabilizers.
n-based, metal soap-based single stabilizers, Ba-Zn-based, B
a-Zn-Mg system, Ca-Zn system, Ca-Zn-Mg
Of one or two or more groups selected from the group consisting of Ca-Zn-Sn-based composite stabilizers, Pb-based single stabilizers and Ba-Zn-based + Pb metal soap-based composite stabilizers. Examples include one or more groups selected from the group. Here, the former group is non-toxic, and the latter group containing lead can be used when toxicity or low toxicity is not a serious problem. These stabilizers are rapidly deteriorated in a composition, especially in response to deterioration of materials under a high temperature environment, by scavenging generated radicals and scavenging / absorbing desorbed hydrochloric acid. And, it delays and suppresses the decomposition reaction. The addition amount is 2 to 15 parts by weight with respect to 100 parts by weight of the vinyl chloride resin,
If it is less than 15 parts by weight, the above-mentioned stabilizing effect cannot be sufficiently obtained, and if it exceeds 15 parts by weight, the miscibility with the material is lowered and the so-called plate-out phenomenon in which the material precipitates out of the system. This is because it is not preferable because it occurs.

The antioxidant used in the soft vinyl chloride resin-based composition of the present invention is phenol-based,
In particular, hindered phenol-based, amine-based, or ester-based antioxidants are listed, and depending on their use, they may be used alone or in combination of two or more. These antioxidants are mainly added to the composition to prevent the deterioration of the above-mentioned polymeric internal plasticizer, but to suppress the oxidative deterioration of the vinyl chloride resin at high temperature. It also functions to improve the heat-resistant life of the composition. Then, the addition amount is based on 100 parts by weight of the vinyl chloride resin.
The amount of 0.2 to 5 parts by weight is because if it is less than 0.2 parts by weight, the effects such as the above-mentioned deterioration prevention cannot be sufficiently obtained, and if it exceeds 5 parts by weight, migration resistance is deteriorated. Is not preferable. However, most of the high molecular internal plasticizers are hydrolytically prone to hydrolysis due to oxidative deterioration at high temperatures, and are additives that must be added within necessary limits.

Examples of the lubricant used in the soft vinyl chloride resin composition of the present invention include amide-based, acrylic resin-based and paraffin-based (particularly polyethylene-based) lubricants. It may be used alone or in combination of two or more. As described above, this lubricant smoothes the softening of the composition of the present invention, the slipperiness between the molecules, and the slipperiness at the interface between the material and the processing machine by using the lubricant in combination with the polymer internal plasticizer. This is for the purpose of maintaining and contributing to mixing stability and processing stability. In particular, the composition of the present invention does not contain a general plasticizer such as phthalic acid ester unlike the ordinary soft vinyl chloride resin-based composition, so that it can be uniformly dispersed as an internal lubricant. It is an essential additive for maintaining good miscibility. Here, the amide-based lubricant is an effective lubricant because it has an effect of suppressing adhesion to the metal surface due to stickiness of the resin (external lubrication effect) with a relatively small amount. On the other hand, polyethylene-based lubricants also have high external lubricity,
Although effective, it requires more addition than amides. In any case, in order to improve the migration resistance, it is necessary to suppress such organic low molecular weight additives as small as possible, and in this sense, the use of amide additives is advantageous. And the addition amount is 1 to 5
The reason why the amount is parts by weight is that if the amount is less than 1 part by weight, the above effects cannot be obtained, and if the amount exceeds 5 parts by weight, migration resistance is deteriorated, which is not preferable.

Examples of the filler used in the soft vinyl chloride resin composition of the present invention include fillers such as calcium carbonate, talc, barium sulfate, zeolite, clay and silica. May be used alone or in combination of two or more. This filler not only plays a role of appropriately adjusting the resin temperature by moderately adjusting the viscosity of the composition and moderately generating heat during kneading, but also improves processability or insulation properties. Or for adjusting the feel of the composition. However, when the composition is to be made transparent (more strictly, to be semi-transparent), it is preferable that no addition be made. The addition amount of less than 200 parts by weight means that when it exceeds 200 parts by weight, not only does the property become transiently brittle and the characteristics deteriorate, but also the kneading property deteriorates and the processed appearance of the product appears. This is because it is not preferable because it causes rough skin.

Further, in the present invention, in addition to the above-mentioned additives, a flame retardant such as antimony trioxide, zinc borate, aluminum hydroxide or magnesium hydroxide may be added depending on its use to obtain a composition. It is also possible to make the material itself flame-retardant, or to add silicon resin or the like as appropriate so as to improve the slidability and the water repellency.

According to the present invention, by such a blending, the function of each additive functions well, the migration resistance is high, and the heat resistance and the workability are excellent, and it has an appropriate flexibility.
A soft vinyl chloride resin-based composition is obtained. This soft vinyl chloride resin-based composition is preferably used, for example, as an insulating coating for a PTC heating element having the structure shown in FIG. This P
In the TC heating element, two electrode conductors 2 and 2 are embedded in a semiconductive composition 1 in which a conductivity-imparting material is mixed in a crystalline polymer to form a heating portion, and a heating portion is formed on the outer periphery of the heating portion. An insulating coating 3 made of the soft vinyl chloride resin composition of the invention is applied. Therefore, in this PTC heating element, there is almost no migration of the plasticizer or the like from the insulating coating 3 to the semiconductive composition 1 side of the heating section, and a heating element having extremely stable characteristics over time can be obtained. Note that the use of the composition of the present invention is not limited to the above-mentioned heating element, and migration of plasticizers and other trace components is a problem, and can be used for food containers, medical equipment, precision wiring systems, etc. it can.

[0022]

EXAMPLES Based on the formulations shown in Tables 1 to 5, the soft vinyl chloride resin composition of the present invention (Examples 1 to 10),
Compositions and conventional products lacking the conditions of the present invention (Comparative Examples 1 to 12) were produced, and softness, migration resistance, heat resistance,
Various tests were conducted on workability and other characteristics. The results are also shown in the table.

Here, regarding the softness, the plastic durometer hardness test method (JIS-K721) is used.
5). The migration resistance was evaluated by bringing the produced composition into contact with a conductive resin and changing its electric resistance. Regarding the heat resistance, the heat resistance test method of the soft polyvinyl chloride compound (JIS-K672
3). Regarding workability, the composition was kneaded, pelletized, and extruded in a flat band shape with a φ25 mm test extruder, and the superiority or inferiority of the appearance was visually determined. Other characteristics, such as flame retardancy, were carried out by a combustion test (JIS-K7201) of a polymer material by an oxygen index method, and transparency, precipitation (plate out), etc. were visually carried out.

[0024]

[Table 1]

[0025]

[Table 2]

[0026]

[Table 3]

[0027]

[Table 4]

[0028]

[Table 5]

From Tables 1 to 5, in the case of the soft vinyl chloride resin compositions of the present invention (Examples 1 to 10), all of the softness, migration resistance, heat resistance, workability, flame retardancy, etc. It can be seen that good results have been obtained. On the other hand, compositions and conventional products lacking the conditions of the present invention (Comparative Examples 1 to 1)
In the case of 2), it can be seen that there is a problem in any of the points.

Next, Comparative Example 1 using the soft vinyl chloride resin composition of the present invention (of Example 1) and the conventional soft vinyl chloride resin composition (Polyester-based polymerization type plasticizer)
No. 1 and those of Comparative Example 12 using only EVA and NBR polymer internal plasticizers) were made into a sheet, and these sheets corresponded to the heating portion of the PTC heating element having the structure shown in FIG. Semiconductive composition sheet (having a resistance value of 100 to
40000 Ω-cm) is sandwiched from above and below, and further sandwiched by a 0.5 mm-thick stainless steel plate on the outside of both sheets of this soft vinyl chloride resin-based sheet.
It was heated to about 00 ° C. Then, it cooled to 20 degreeC (normal temperature), and measured the change of the resistance value of the said semiconductive composition sheet over time in this normal temperature state. To show the result,
It was as shown in FIG. In the figure, the characteristic line 10 is the product of the present invention of Example 1, the characteristic line 10 is the conventional product of Comparative Example 11, and the characteristic line 12 is the conventional product of Comparative Example 12. It can be seen from FIG. 2 that the soft vinyl chloride resin composition of the present invention shows almost no change in electric resistance and no migration of contained substances. On the other hand, in the conventional soft vinyl chloride resin-based composition,
It can be seen that the change in electric resistance is large and the migration of contained substances such as plasticizers increases with time.

[0031]

As described above, according to the invention of claim 1, 2 or 3 of the present invention, it has a high degree of migration resistance and also has an excellent flexibility such as heat resistance and workability. A soft vinyl chloride resin-based composition is obtained. Further, according to the invention of claim 4 of the present invention, a stable PTC heating element with little characteristic change over time can be obtained. Further, in the soft vinyl chloride resin composition according to the invention of claim 1, 2 or 3 according to the present invention, there is almost no migration of plasticizers and other trace components, so that it is applied to food containers, medical devices, etc. In this case, high safety can be obtained, and when it is applied to a precision wiring system, etc., it does not contaminate surrounding equipment that comes into contact with it, and it is also safe and highly reliable. .

[Brief description of drawings]

FIG. 1 is a partial vertical perspective view showing a PTC heating element using a soft vinyl chloride resin composition of the present invention as an insulating coating.

FIG. 2 is a graph showing the results of a migration resistance test between the soft vinyl chloride resin composition of the present invention and a conventional product.

[Explanation of symbols]

 1 Semi-conductive composition 2 Electrode conductor 3 Insulation coating

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C08K 3/26 KGL C08K 3/26 KGL 3/30 KGM 3/30 KGM 3/34 KGN 3/34 KGN 3/36 3/36 5/098 KGX 5/098 KGX 5/10 KKY 5/10 KKY 5/13 KHA 5/13 KHA 5/17 KHE 5/17 KHE 5/20 KHF 5/20 KHF C08L 9 / 02 LBG C08L 9/02 LBG LBJ LBJ LBK LBK 23/08 LCB 23/08 LCB LCJ LCJ LCK LCK 23/28 LDA 23/28 LDA 33/06 LJD 33/06 LJD H01B 1/12 H01B 1/12 A 3 / 44 3/44 B H05B 3/14 H05B 3/14 A

Claims (4)

[Claims] 1. 1 or 2 selected from 100 parts by weight of vinyl chloride resin and a polymer resin of nitrile butadiene rubber (NBR), acrylic rubber, EVA, EEA, chlorinated polyethylene (CPE). 50 to 500 parts by weight of the above polymeric internal plasticizer, and a Sn-based, Ba-based, Zn-based, metal soap-based independent stabilizer,
Ba-Zn system, Ba-Zn-Mg system, Ca-Zn system, C
2-15 parts by weight of one or more stabilizers selected from a-Zn-Mg-based and Ca-Zn-Sn-based composite stabilizers, and phenol-based, amine-based, or ester-based antioxidants 0.2 or more of one or more antioxidants selected from among the agents
To 5 parts by weight and 1 to 5 parts by weight of one or more lubricants selected from the group consisting of amide-based, acrylic resin-based, and paraffin-based lubricants. 2. 1 or 2 selected from 100 parts by weight of vinyl chloride resin and a polymer resin of nitrile butadiene rubber (NBR), acrylic rubber, EVA, EEA, chlorinated polyethylene (CPE). 50 to 500 parts by weight of the above-mentioned polymeric internal plasticizer, one or more stabilizers 2 selected from Pb-based single stabilizers and Ba-Zn-based + Pb metal soap-based composite stabilizers .About.15 parts by weight, and one or more antioxidants 0.2 selected from the group consisting of phenol-based, amine-based, or ester-based antioxidants 0.2
To 5 parts by weight and 1 to 5 parts by weight of one or more lubricants selected from the group consisting of amide-based, acrylic resin-based, and paraffin-based lubricants. 3. The composition according to claim 1, wherein one or more fillers selected from fillers of calcium carbonate, talc, barium sulfate, zeolite, clay, or silica are added to the composition. A soft vinyl chloride resin composition characterized by being added in an amount of less than 1 part by weight. 4. A PTC heating element comprising a semiconductive composition obtained by mixing a conductivity-imparting material in a crystalline polymer and burying two electrode conductors in a heat generating portion and applying an insulating coating. ,
A PTC heating element comprising the soft vinyl chloride resin composition according to claim 1, 2 or 3 as an insulating coating.