JPS584721B2 - Polyethylene materials used for various purposes - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for producing chlorinated polyethylene.

For more details, see melt index 0.1-309/
In chlorinating high-density polyethylene particles or powder with a density of 0.939/cc or more in an aqueous suspension for 10 minutes,
105-1 until the degree of chlorination reaches 10-35 by weight
Chlorination at a temperature of 15 °C, then the final degree of chlorination is 15
The melt index is at least 0.19/10 minutes, characterized by chlorination at a temperature lower than the chlorination temperature in the previous stage and at a temperature of 90 to 105 °C until reaching ~50 weight ratio, at least 30 minutes. The present invention relates to a method for producing crystalline chlorinated polyethylene having a heat resistance of at least 30% and a residual crystallinity of at least 30%.

Methods for producing chlorinated polyethylene by chlorinating particulate or powdered polyethylene in an aqueous suspension are known in the art.

The properties of the chlorinated polyethylene obtained by this method vary depending on the structure, molecular weight, and chlorination temperature of the raw material polyethylene, ranging from rubber-like materials with low residual crystallinity to rubber-like materials with high residual crystallinity. It has a wide range of properties, including hard resin-like materials.

Chlorinated polyethylene with low residual crystallinity has soft rubber elasticity and excellent properties such as flame retardancy, weather resistance, chemical resistance, and electrical properties, so chlorinated polyethylene cannot be used alone. Of course, it is also used as a modifier for other synthetic resins (eg, vinyl chloride resins and olefin resins), particularly as an impact resistance agent, flame retardant agent, and the like.

On the other hand, hard chlorinated polyethylene (crystalline chlorinated polyethylene) with a high degree of residual crystallinity does not have much use, and at present, almost no research and development has been conducted on it.

However, in recent years, the toxicity of vinyl chloride monomers and plasticizer pollution have become a hot topic in the vinyl chloride resin industry, so there is a strong demand for alternative materials to vinyl chloride resin, especially in the food and medical fields. has been done.

In addition, in recent years, due to the need for fire safety, the demand for flame retardant polymer materials has been strengthened, and over the years, the demand for flame retardant properties has increased particularly in fields such as electric wire materials, electrical parts, automobile parts, and building materials. As the market becomes more stringent, expectations for flame-retardant polymer materials are increasing, and crystalline chlorinated polyethylene, which had previously received little attention, is suddenly attracting attention.

Known methods conventionally used to produce crystalline chlorinated polyethylene include reducing the degree of chlorination of chlorinated polyethylene (for example, reducing the degree of chlorination to 15% by weight or less).
A method of chlorinating at a considerably lower chlorination temperature (for example, 100° C. or lower) than the melting temperature range of raw polyethylene is known.

The former method has a residual crystallinity close to that of the raw material polyethylene, but the degree of chlorination (chlorine content) is low, so it is not satisfactory as a flame-retardant polymer material.

In the latter method, the chlorination reaction is carried out at a temperature considerably lower than the melting temperature range of the raw material polyethylene, so the chlorination reaction rate is extremely slow, and only the surface layer of the raw material polyethylene is densely chlorinated. It has the disadvantage of poor heat resistance.

From this point of view, the present inventors have made various studies to improve the above-mentioned drawbacks and produce crystalline chlorinated polyethylene with excellent heat resistance.
In chlorinating high-density polyethylene particles or powder with a density of 0.93 g/cc or more in an aqueous suspension for 10 minutes,
105-1 until the degree of chlorination reaches 10-35 by weight
Chlorination at a temperature of 15 °C, then the final degree of chlorination is 15
If the chlorination is carried out at a temperature lower than the chlorination temperature in the previous stage and at a temperature of 90 to 105°C until the weight reaches 50%, fusion of the chlorinated polyethylene particles will occur as the chlorination progresses. The present invention was achieved based on the discovery that the chlorinated polyethylene has an extremely fast chlorination reaction rate without causing agglomeration, and the resulting chlorinated polyethylene has a high residual crystallinity and has excellent heat resistance and moldability.

The effect of the two-stage chlorination method in the present invention is extremely remarkable, and although the details of its mechanism of action are not necessarily clear, the chlorination temperature in the first stage is 105 to 115°C, just before the raw material polyethylene begins to melt significantly. This is the temperature just before melting while retaining most of the crystals in the raw polyethylene, so chlorine quickly diffuses into the amorphous region inside the raw polyethylene and immediately reacts with the raw polyethylene. do.

This first-stage chlorination causes minute structural changes inside the raw polyethylene, lowering the melting temperature range, so even if the second-stage chlorination temperature is low, the amorphous region inside the polyethylene is affected. Easy diffusion of chlorine.

Therefore, this diffused chlorine reacts not only with the surface layer of polyethylene but also with the amorphous region inside the polyethylene, and the chlorination is uniformly carried out from the surface of the polyethylene to the amorphous region inside. It is assumed that crystalline chlorinated polyethylene having a fast chlorination reaction rate and excellent heat resistance and moldability can be easily obtained.

This fact is a surprising effect that cannot be obtained even if raw polyethylene is chlorinated in a chlorinated hydrocarbon under the same conditions as the present invention, and the benefits are significant.

The present invention provides chlorination of high-density polyethylene particles or powder in an aqueous suspension at a temperature of 105-115°C until the degree of chlorination reaches 10-35% by weight,
Next, the temperature is lower than the chlorination temperature in the previous step until the final chlorination degree reaches 15 to 50% by weight, and 90 to 10% by weight.
At least 0, characterized in that it chlorinates at a temperature of 5°C.
．． Melt index of 1 g/10 min, preferably 0.
Crystals having a melt index of 1 to 109/10 minutes, a heat resistance of at least 30 minutes, preferably 30 to 120 minutes, and a residual crystallinity of at least 30 coefficients or higher, preferably 30 to 95 coefficients. The present invention relates to a method for producing polyethylene chlorinated polyethylene.

The raw material polyethylene suitable for carrying out the method of the present invention has a melt index (load of 2.16 ky, temperature of 190
°C) is 0.1 to 30 g/10 minutes, preferably 1 to 20 g
/10 minutes density is 0.93g/cc or more, preferably 0
．． It is high density polyethylene of 949/cc or more.

These high-density polyethylenes have a crystallinity of over 70% and a
It is a linear polyethylene with 1.5 methyl branches per 00 carbon.

High-density polyethylene with a melt index of more than 30 g/10 minutes is undesirable because the heat resistance of the resulting crystalline chlorinated polyethylene is significantly reduced; High-density polyethylene with a density of less than 1 g/10 min is not preferable because the resulting crystalline chlorinated polyethylene has poor moldability.

Furthermore, since low-density polyethylene having a density of 0.93 g/cc or less generally has a branched structure in its molecules, tertiary carbon is preferentially chlorinated during chlorination.

Therefore, the crystalline chlorinated polyethylene obtained has a drawback of extremely poor heat resistance.

The raw material polyethylene used in the method of the present invention is produced by a medium pressure method using a metal oxide such as a chromium oxide or molybdenum oxide catalyst, or a low pressure method using a Ziegler-Natsuta catalyst.

Suitable chlorination temperatures for carrying out the process of the invention include a temperature range of 105-115°C for the first stage, a temperature lower than the chlorination temperature of the first stage for the second stage, and 90-105°C.
temperature range.

If the chlorination temperature in the first stage is 105°C or lower, the diffusion rate of chlorine into the raw polyethylene is slow, so the chlorination reaction rate is slow, and most of the chlorine reacts on the surface of the raw polyethylene, so the surface Chlorine density increases dramatically.

Therefore, the heat resistance of the crystalline chlorinated polyethylene obtained is significantly reduced.

On the other hand, when the chlorination temperature in the first stage exceeds 115C, the residual crystallinity of the resulting chlorinated polyethylene decreases significantly, and not only does it have rubber elasticity, but also the chlorinated polyethylene particles melt together in the aqueous suspension. This is undesirable because it will lead to a baby boom.

In addition, if the chlorination temperature in the second stage is 90°C or lower, although crystalline chlorinated polyethylene is obtained, the chlorine does not diffuse sufficiently into the inside of the particles, so the chlorination reaction rate is slow, and the crystalline chlorine obtained is Polyethylene has the disadvantage of poor heat resistance due to its non-uniform chlorine distribution.

On the other hand, if the chlorination temperature in the second stage exceeds 105°C, not only will the residual crystallinity of the obtained chlorinated polyethylene drop significantly, but also the chlorinated polyethylene particles may fuse together and form agglomerates, which is not preferable. do not have.

In the method of carrying out the present invention, in the first step, chlorination is carried out until the degree of chlorination reaches 10 to 35 parts by weight, and then in the second stage, chlorination is carried out until the final degree of chlorination reaches 15 to 50 parts by weight. is necessary.

If the degree of chlorination in the first stage is 10% by weight or less, the degree of chlorination is low and no change in the fine structure inside the raw polyethylene occurs, so a reduction in the melting temperature range cannot be expected.

Therefore, the second stage chlorination temperature is not preferable because it becomes difficult for chlorine to diffuse into the amorphous region inside the polyethylene and the chlorine distribution becomes non-uniform.

On the other hand, if the degree of chlorination in the first stage exceeds 35% by weight, not only will the crystals of the raw polyethylene be destroyed and the desired crystalline chlorinated polyethylene cannot be obtained, but in some cases, the chlorinated polyethylene particles may interact with each other. This is undesirable because it causes fusion and formation of lumps.

Further, if the final degree of chlorination is 15% by weight or less, the degree of chlorination is low and the material is not satisfactory as a flame-retardant polymer material, which is not preferable.

On the other hand, if the final degree of chlorination exceeds 50% by weight, it is not preferable because not only the chlorination rate becomes slow but also the heat resistance of the obtained chlorinated polyethylene decreases.

The production of crystalline chlorinated polyethylene by the method of the present invention includes:
This is carried out by suspending particulate or powdered polyethylene in an aqueous medium.

In order to maintain this aqueous suspension state, it is preferable to add a small amount of emulsifying agent or suspending agent.

At this time, radical generators such as penzoyl peroxide, azobisisobutyronitrile and hydrogen peroxide, antifoaming agents such as light silicone oil, and other additives may be added as necessary.

Chlorine can be used alone in gaseous form or diluted with a suitable inert gas.

In this case, the chlorine introduction pressure is 5 kg/cr2 or less.

The progress of chlorination can be determined by measuring the weight loss of supplied chlorine, but can also be determined by measuring the amount of hydrochloric acid generated.

In the first stage of chlorination, chlorine is supplied at a temperature of 105-115°C until the degree of chlorination reaches 10-35% by weight.

After the degree of chlorination reaches 10-35% by weight, the temperature of the suspension system is lower than the chlorination temperature of the first stage and 90-35% by weight.
The temperature is lowered to 105° C. and chlorine is supplied until a predetermined degree of chlorination is reached.

The thus obtained chlorinated polyethylene is washed with water to remove hydrochloric acid and the like, and then dried.

The crystalline chlorinated polyethylene obtained by the method of the present invention not only has a high residual crystallinity and excellent heat resistance and moldability, but also has weather resistance, sedimentation resistance, electrical properties, gas permeability resistance, and flame retardance. Due to its excellent properties such as durability, it can be used, for example, as electric wire covering materials, construction materials, various window frame materials,
It is useful as various packaging materials, various electrical component materials, packings, gas pipes, hoses, floor tiles, sheets, leather, foamed products, multilayer molded products, and various other molding materials.

Furthermore, the crystalline chlorinated polyethylene obtained by the method of the present invention can be used in combination with other synthetic resins such as olefin resins, vinyl chloride resins, and styrene resins.

Furthermore, processability can be improved by mixing with amorphous chlorinated polyethylene.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

In addition, each physical property value in an Example and a comparative example was performed according to the following.

Yield Point Strength Measure JI83 test piece at a tensile speed of 200 mx/f It is expressed as a percentage of the crystal melting area.

Therefore, it shows residual crystallinity. Average chlorination reaction rate is the total amount of chlorine consumed in the chlorination reaction divided by the reaction time.

Measurements were made at a melt index load of 2.16 kp and a temperature of 190°C.

Measurement of a 100 modulus JI No. 83 test piece at a tensile rate of 200 IL/min Example 1 In a 100 liter glass-lined autoclave, 80 liters of water, 90 g of sodium lauryl sulfate, a melt index of 1.1 g and a density of 0.959 g/CC were placed in a 100 liter glass-lined autoclave for 710 minutes. Polyethylene powder (passes through a 10 mesh sieve)
10k9 was added and stirred.

After heating this mixture to 110°C, chlorine was introduced and 2
．． The chlorine pressure was 7 atm, and chlorination was carried out until the degree of chlorination reached 20% by weight.

Then, the chlorination temperature was lowered to 90° C., and chlorination was continued until the degree of chlorination was 32% by weight.

The total reaction time to reach a final degree of chlorination of 32 parts by weight was approximately 4 hours.

The properties of the chlorinated polyethylene thus obtained are shown in Table 1.

In Table 1, Comparative Example 1 was obtained by chlorinating the same raw materials as in this example at a temperature of 110°C until the degree of chlorination reached 32% by weight without lowering the temperature midway through. In addition, in Comparative Example 2, the same raw material as in this example was subjected to the first stage chlorination at a temperature of 110°C, and after the degree of chlorination reached 20% by weight, the temperature was raised to 80°C. The temperature was lowered and chlorination was carried out until the degree of chlorination reached 32% by weight.

In Comparative Example 3, the same raw material as in this Example was chlorinated at a temperature of 90°C until the degree of chlorination reached 32% by weight. In Comparative Example 4, the same raw material as in this Example was chlorinated. The first stage of chlorination of the raw material is carried out at a temperature of 120°C until the degree of chlorination reaches 20 parts by weight, then the temperature is lowered to 100°C and chlorination is carried out until the degree of chlorination reaches 32 parts by weight. It is something that

Example 2 Into the autoclave used in Example 1, 80 liters of water, 100 g of sodium lauryl sulfate, and a melt index of 5.0 g.
10 kg of polyethylene powder having a density of 0.960 g/cc (passed through a 10 mesh sieve) was added and stirred for 10 minutes.

After heating this mixture to 105C, chlorine was introduced and
．． The chlorine pressure was set to 0 atm, and chlorination was carried out until the degree of chlorination reached 30% by weight.

Then, the chlorination temperature was lowered to 100° C., and further chlorination was continued until the final degree of chlorination reached 40% by weight.

The total reaction temperature until the final degree of chlorination reached 40 parts by weight was about 5 hours.

Table 2 shows the properties of the obtained chlorinated polyethylene.

In addition, in Comparative Example 5 in Table 2, the first stage of chlorination was performed at a temperature of 105°C using the same raw materials as in this example, and after the degree of chlorination reached 37% by weight, the temperature was increased. The temperature was lowered to 100°C and chlorination was carried out until the final degree of chlorination reached 40% by weight.

In Comparative Example 6, the same raw material as in this example was subjected to the first stage chlorination at a temperature of 110°C, and after the degree of chlorination reached 5% by weight, the temperature was lowered to 90°C and the final chlorination was carried out. Chlorination was carried out until the degree reached 40% by weight.

Example 3 The autoclave used in Example 1 was charged with 80 liters of water, 90 g of ethylene oxide-propylene oxide copolymer, a melt index of 20.0 g/10 minutes, and a density of 0.95.
10 kg of 4 g/cc polyethylene powder (passed through a 10 mesh sieve) was added and stirred.

After heating this mixture to 115C, chlorine was introduced and
．． The chlorine pressure was set to 0 atm, and chlorination was carried out until the degree of chlorination reached 25% by weight.

Then, the chlorination temperature was lowered to 100° C., and further chlorination was continued until the final degree of chlorination reached 35% by weight.

The total reaction time to reach a final degree of chlorination of 35 parts by weight was approximately 4 hours.

The average chlorination reaction rate of the obtained chlorinated polyethylene was 0.
．． 267kg, Cl2/kg. P.E. hr, residual crystallinity 35, heat resistance 35 minutes, 100 modulus 80kg/
cd2, yield point strength of 89 K9/cm4, and melt index of 9.5 g/10 minutes.

Example 4 Into the autoclave used in Example 1, 80 liters of water and 100 g of ethylene oxide/propylene oxide copolymer were added.
, melt index 6.5g/10 minutes, density 0.9
5 g/cc of polyethylene powder (passed through a 10 mesh sieve) 10k9 was added and stirred.

After heating this mixture to 105°C, chlorine was introduced and
．． The chlorine pressure was set to 0 atm, and chlorination was carried out until the degree of chlorination reached 10% by weight.

Then, the chlorination temperature was lowered to 100° C., and further chlorination was continued until the final degree of chlorination reached 20% by weight.

The total reaction time until the final degree of chlorination reached 20 parts by weight was approximately 5 hours.

The average chlorination reaction rate of the obtained chlorinated polyethylene was 2
50kg. C12/k9. PE-hr, residual crystallinity 70
Heat resistance: 35 minutes, 100% modulus: 155kg/C
rl2, yield point strength of 160 kg/ffl, and tart index of 2.8 g/10 minutes.

Example 5 Into the autoclave used in Example 1, 80 liters of water, 90 g of ethylene oxide-propylene oxide copolymer,
Melt index 15.0g/10 minutes and density 0.9
10 kg of 62 g/cc polyethylene powder (passed through a 10 mesh sieve) was added and stirred.

After heating this mixture to 115°C, chlorine was introduced and 2
．． The chlorine pressure was 5 atm, and chlorination was carried out until the degree of chlorination reached 20% by weight.

Then, the chlorination temperature was lowered to 105C, and the degree of chlorination was 3.
Further chlorination was continued until a weight of 5% was reached.

The total reaction time to reach a final degree of chlorination of 35 parts by weight was approximately 4 hours.

The average chlorination reaction rate of the obtained chlorinated polyethylene was 0.
．． 267kg. Cl2/kg. P.E. hr, residual crystallinity 35%, heat resistance 42 minutes, 100% modulus 74kg/
cm2, yield point strength of 88 kg/cm2, and melt index of 7.0 g/10.

Claims (1)

[Claims] 1 When chlorinating high-density polyethylene particles or powder with a melt index of 0.1 to 309/10 minutes and a density of 0.93 g/cc or more in an aqueous suspension, the degree of chlorination is 1.
Chlorination is carried out at a temperature of 105 to 115°C until the degree of chlorination reaches 0 to 35% by weight, and then at a temperature lower than the previous chlorination temperature until the final degree of chlorination reaches 15 to 50% by weight.
and a melt index of at least 0.1 g/10 min, characterized in that it chlorinates at a temperature of 90 to 105 °C,
A method for producing crystalline chlorinated polyethylene having a heat resistance of at least 30 minutes and a residual crystallinity of at least 30%.