KR20180061682A - Method for Preparing High Density Polyethylene Powder - Google Patents

Abstract

The present invention relates to a method for preparing high density polyethylene powder. More specifically, the present invention provides a method which can prepare high density polyethylene powder suitable as an asphalt reinforcing agent by having excellent elasticity, tensile strength, weather resistance and heat resistance, and having a micro-particle shape by using a high-speed spinning nozzle rotating at high speed.

Description

TECHNICAL FIELD The present invention relates to a high density polyethylene powder,

The present invention relates to a method for producing high density polyethylene powder which can be used as an asphalt reinforcing material.

High density polyethylene (HDPE) is a synthetic resin based on ethylene and has excellent mechanical properties, heat resistance and cold resistance, and recent studies for application as materials in various fields are continuing. For example, high-density polyethylene is used as a raw material for shopping plastic bags, electric wires, hoses, beer cans, milk containers, water pipes, and gas pipes.

However, the high-density polyethylene has a problem in terms of processability and has been used in the form of pellets rather than in the form of a fine powder. Thus, it has been difficult to apply it to various fields of high-density polyethylene.

Therefore, attempts have been made to produce high-density polyethylene in powder form rather than in pellet form. In fact, there has been proposed a technique for producing a polyethylene spherical powder having a micro-unit diameter of high-density polyethylene by emulsion crystallization instead of mechanical pulverization ) And a polyolefin solution prepared by mixing a modified polyolefin (high density polyethylene) and an organic solvent to cool the polyolefin solution to form a polyolefin powder having an average particle size of microunits (Patent Document 002).

However, the techniques of producing high-density polyethylene powders disclosed in these patent documents have problems in that the yield of the polyethylene powder having an appropriate size is poor and the powder is too large or too small in the manufacturing process, There has been a problem in the process of separately removing the used solvent.

Therefore, it is required to develop a new technology capable of producing a high-density polyethylene powder having elasticity, tensile strength, weather resistance, and heat resistance required as an asphalt reinforcing material through a simple process while producing a high-density polyethylene powder.

Korean Patent No. 0435518, " Method and Apparatus for Producing Polyethylene Spherical Powder with Improved Productivity " Korean Patent No. 1237741, "Polyolefin Powder and Method for Producing the Same"

As a result of various studies to solve the above problems, the inventors of the present invention have found that it is possible to produce high-density polyethylene powder in micro units when a high-density polyethylene-containing resin is frozen sprayed using a high- Thereby completing the invention.

Accordingly, an object of the present invention is to provide a method for producing a high-density polyethylene powder which can produce a high-density polyethylene powder having a uniform size at a high yield by using a high-density polyethylene resin as a starting material.

In order to accomplish the above object, there is provided a method for manufacturing a molded product, comprising the steps of: (S1) melting a high density polyethylene (HDPE) resin and an elastomer resin to prepare a molten resin;

(S2) An acrylic graft resin and 4,4'-bis (a, a-dimethylbenzyldiphenylamine) [4,4'-bis (alpha, ;

(S3) preparing a high-density polyethylene powder by cryo-spraying the mixed resin using a high-speed spin injection nozzle under a liquid nitrogen gas; And

(S4) a step of corona spinning the high-density polyethylene powder.

In the step (S1), 100 parts by weight of the high-density polyethylene resin and 2 to 3 parts by weight of the elastomer resin can be melted. In the step (S2), 100 parts by weight of the high-density polyethylene resin of the step (S1) 1 to 10 parts by weight of a resin and 5 to 10 parts by weight of 4,4'-bis [alpha], [alpha] -dimethylbenzyldiphenylamine) Can be produced.

In addition, the high-speed rotation injection nozzle can rotate at 1300 to 1700 rpm, air can be injected into the high-speed rotation injection nozzle, and the pressure of the air injected into the high-speed rotation injection nozzle is more than 0 psi and less than 5 psi Lt; / RTI >

According to the present invention, a high-density polyethylene powder can be produced by a mechanical method using a high-speed rotation injection nozzle, so that the process can be simplified, thereby improving the process efficiency.

In addition, since the mixed resin produced by melting the high-density polyethylene and the elastomer resin is injected through the high-speed spin injection nozzle, the high-density polyethylene powder can have the shape of spherical particles having a uniform size, The yield of the high-density polyethylene powder can be improved.

The high-density polyethylene powder thus produced has an apparently uniform size and shape, and is excellent in elasticity, tensile strength, weather resistance, and heat resistance, and thus is suitable as an asphalt reinforcing material.

Hereinafter, the present invention will be described in detail in order to facilitate understanding of the present invention.

The terms and words used in the present specification and claims should not be construed in an ordinary or dictionary sense and the inventor can properly define the concept of the term to describe its invention in the best possible way It should be construed as meaning and concept consistent with the technical idea of the present invention.

The present invention relates to (S1) a process for producing a molten resin by melting an HDPE (High Density Polyethylene) resin and an elastomer resin;

(S2) An acrylic graft resin and 4,4'-bis (a, a-dimethylbenzyldiphenylamine) [4,4'-bis (alpha, ;

(S3) preparing a high-density polyethylene powder by cryo-spraying the mixed resin using a high-speed spin injection nozzle under a liquid nitrogen gas; And

(S4) a step of corona spinning the high-density polyethylene powder.

Hereinafter, the method for producing a high-density polyethylene powder according to the present invention will be described in detail for each step.

In step (S1), a molten resin can be produced by melting HDPE (High Density Polyethylene) resin and an elastomer resin.

The high-density polyethylene resin may be in the form of a pellet having a particle diameter of 5 to 10 mm. When a pellet-shaped high-density polyethylene resin having such a size is used, it melts together with the elastomer resin at a melting temperature of 140 to 160 ° C to form a molten resin can do.

The elastomer resin may be one selected from the group consisting of a polyester-carbonate block copolymer, a polyurethane-ester block copolymer, a polyamide-ether block copolymer and a mixture thereof, and in particular, a polyurethane- When the co-polymer is used, the high-density polyethylene resin to be produced may have excellent elasticity.

The elastomer resin may be used for imparting elasticity to the high-density polyethylene powder. In the step (S3), the powder is not broken due to the spraying force and the rotational force of the high-speed rotation injection nozzle during powder production using the high- Or the like.

In the step (S1), 100 parts by weight of the high-density polyethylene resin and 2 to 3 parts by weight of the elastomer resin may be melted. If the amount of the elastomer resin is less than 2 parts by weight, the elasticity of the high- The powder may be broken by the spraying force and the rotational force at the time of manufacture. If the amount is more than 3 parts by weight, the elasticity of the high-density polyethylene powder may excessively decrease and the strength may not be suitable as an asphalt reinforcing material.

In step (S2), an acrylic graft resin and 4,4'-bis [alpha], [alpha] -dimethylbenzyldiphenylamine) Whereby a mixed resin can be produced.

In step (S2), 1 to 10 parts by weight of an acrylic graft resin and 5 to 10 parts by weight of 4,4'-bis (a, a-dimethylbenzyl-disphenylamine) are mixed with 100 parts by weight of the high-density polyethylene resin Whereby a mixed resin can be produced.

If the content of the acrylic graft resin is less than 1 part by weight, the weather resistance may be lowered. If the content of the acrylic graft resin is less than 10 parts by weight, the weather resistance may not be further strengthened. When 5 parts by weight is used, the weather resistance is enhanced and the physical properties such as tensile strength, elasticity and heat resistance are also excellent, which is preferable.

The acrylic graft resin may be obtained by grafting 40 to 90% by weight of an aromatic vinyl compound-cyanide vinyl compound copolymer to 10 to 60% by weight of a (meth) acrylic rubber, and the aromatic vinyl compound- An aromatic vinyl compound, and a vinyl cyanide compound in an amount of 60 to 80% by weight and 20 to 40% by weight, respectively. The acrylic graft resin having such a composition may be advantageous for enhancing the weatherability of the high-density polyethylene powder.

On the other hand, after a molten resin in which only the high-density polyethylene resin is melted in the step (S1) is produced, an elastomer resin, an acrylic graft resin and a 4,4'-bis (a, a-dimethylbenzyl- In the step S3, the powder is not formed even by the high-speed rotation injection nozzle and is broken into pellets having a large size. In this case, as described above, ), It is preferable to prepare a mixed resin in step (S2) after producing a molten resin in which the high-density polyethylene resin and the elastomer resin are melted.

In the step (S3), the high-density polyethylene powder can be produced by free-spraying the mixed resin using a high-speed rotary injection nozzle in the presence of liquid nitrogen gas.

The high-speed rotation injection nozzle may form a high-density polyethylene powder by a spraying force and a rotational force, and the mixed resin dispersed by the rotational force after the mixed resin is dispersed by the spraying force may be a powder having a spherical particle shape.

If the rotational speed is less than 1300 rpm, the rotational force is weak and spherical powder particles may not be formed. If the rotational speed is more than 1700 rpm, the rotational force is excessive and the powder particles are spherical Non-deformed form, such as a collapsed or elongated form.

On the other hand, by injecting air into the high-speed rotation injection nozzle, the particle diameter and shape of the high-density polyethylene powder can be controlled by further strengthening the spraying force and the rotational force.

The pressure of the air to be injected into the high-speed rotary injection nozzle may be more than 0 psi and not more than 5 psi. If the air pressure is more than 5 psi, the injection force and the rotational force are excessively excessive. Instead, the high-density polyethylene powder is not formed, Modified forms of the particles can be formed.

If no liquid nitrogen gas is present in step (S3), powder particles are not formed. Therefore, it is preferable to carry out the process under liquid nitrogen gas during powder production by the high-speed rotation injection nozzle.

In step (S4), the high-density polyethylene powder may be subjected to corona radiation treatment, and the surface of the high-density polyethylene powder may be surface-modified to have fine irregularities by the corona radiation treatment.

When the surface modified high density polyethylene powder is used as an asphalt reinforcing material, it is possible to enhance the strength of the asphalt by improving the mixing and adhesion with the ascon.

The corona radiation treatment may be performed under the condition of 50 to 80 W / m ² / min. If the corona radiation treatment is performed at less than 50 W / m ² / min, the surface modifying effect of the high density polyethylene powder may be insignificant. / m < ² > / min, the physico-chemical properties of the high-density polyethylene powder may be altered and it may be difficult to use it as an asphalt reinforcing material.

The high-density polyethylene powder produced by the above-described method may be spherical particles having a particle diameter of 0.5 to 5 탆. In the case of the high-density polyethylene powder of this type, it may exhibit elasticity, tensile strength, weatherability and heat resistance suitable as an asphalt reinforcement.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope and spirit of the invention as disclosed in the accompanying claims. Changes and modifications may fall within the scope of the appended claims.

In the following Examples and Comparative Examples, a negative electrode was prepared according to the composition as shown in Table 1 below.

Molten resin
(Parts by weight) Mixed resin
(Parts by weight) High-speed rotation
Injection nozzle Corona radiation treatment
(W / m ² / min) High density polyethylene resin
Elastomer
Suzy Acrylic graft resin 4,4'-bis (a, a-dimethylbenzyl-disphenylamine) Liquid nitrogen gas Rotation speed
(rpm) air
(psi) Polyurethane-ester block copolymer Example 1 100 2.5 5 8 ○ 1500 - 70 Example 2 100 2.5 5 8 ○ 1500 3 70 Comparative Example 1 100 2.5 5 8 ○ 1500 - 70 Comparative Example 2 100 - 5 8 ○ 1500 - - Comparative Example 3 100 2.5 - 8 ○ 1500 - 70 Comparative Example 4 100 2.5 5 - ○ 1500 - 70 Comparative Example 5 100 2.5 5 8 X 1500 - 70 Comparative Example 6
100 2.5 5 8 ○ 1500 - 70 After melting the high-density polyethylene resin, a mixed resin was prepared by mixing an elastomer resin, an acrylic graft resin and 4,4'-bis (a, a-dimethylbenzyl-disphenylamine)

Example  1: Production of high density polyethylene powder

One- 1. Melt resin  Produce

And 2.5 parts by weight of a polyurethane-ester block copolymer together with 100 parts by weight of a pellet-shaped high-density polyethylene resin having a particle diameter of 7 mm were melted at 150 DEG C to prepare a molten resin.

1-2. Mixed Resin Manufacturing

5 parts by weight of an acrylic graft resin and 4 parts by weight of 4,4'-bis (a, a-dimethylbenzyl-diphenylamine) were mixed with 100 parts by weight of the high-density polyethylene resin, And 8 parts by weight of 4'-bis (a, a-dimethylbenzyl-disphenylamine) were mixed to prepare a mixed resin.

At this time, the acrylic graft resin is obtained by grafting 60 wt% of an aromatic vinyl compound-cyanide vinyl compound copolymer to 40 wt% of a (meth) acrylic rubber, and the aromatic vinyl compound-cyanide vinyl compound copolymer is an aromatic vinyl compound 70 By weight and 30% by weight of a vinyl cyanide compound.

1-3. Production of high-density polyethylene powder

The mixed resin was cryo-sprayed at -50 ° C using a high-speed spin injection nozzle rotating at 1500 rpm under liquid nitrogen gas to prepare a high-density polyethylene powder.

1-4. Corona Radiation Treatment

The high-density polyethylene powder was subjected to spinning treatment under the condition of 70 W / m ² / min.

Example  2: Production of high density polyethylene powder

The same procedure as in Example 1 was carried out except that the mixture was sprayed with air at a pressure of 3 psi during the spraying of the mixed resin using the high-speed spin injection nozzle in 1-3 above to produce a high-density polyethylene powder.

Comparative Example  1: corona Radiation treatment  Manufacture of High Density Polyethylene Powder without

The high density polyethylene powder was prepared in the same manner as in Example 1 except that the corona discharge treatment of 1-4 was not carried out.

Comparative Example  2: Production of high-density polyethylene powder without elastomer resin

A high density polyethylene powder was prepared in the same manner as in Example 1 except that no elastomer resin was used.

Comparative Example  3: Acrylic Graft  Production of high-density polyethylene powder without resin

A high density polyethylene powder was prepared in the same manner as in Example 1 except that no acrylic graft resin was used.

Comparative Example 4: 4 ,4'- Bis ( a, a - Dimethylbenzyl - Disphenylamine Production of high-density polyethylene powder without

The high density polyethylene powder was prepared in the same manner as in Example 1 except that 4,4'-bis (a, a-dimethylbenzyl-disphenylamine) was not used.

Comparative Example  5: Production of high-density polyethylene powder without liquid nitrogen gas

The high density polyethylene powder was prepared in the same manner as in Example 1 except that no nitrogen gas was used.

Comparative Example  6: Only the high-density polyethylene resin was melted The molten resin  To produce high-density polyethylene powder

The procedure of Example 1 was repeated, except that only a high-density polyethylene resin was melted in the step 1-1 to prepare a molten resin, and then the acrylic resin and the 4,4'-bis (a , a-dimethylbenzyl-disphenylamine) were mixed to prepare a mixed resin.

The elasticity, tensile strength, weather resistance and heat distortion temperature (heat resistance) of the high-density polyethylene powder prepared in Examples and Comparative Examples were measured and the results are shown in Table 2.

(1) elasticity

The value at 100% elongation was determined as the elastic modulus by the test method of KSM 3006-98.

(2) Tensile strength

Measured by the test method of ASTM D 412-'98

(3) Weatherability

According to the ISO-105 specification, the weatherability of the test specimens prepared by injection molding was evaluated by Xenon light source, black panel temperature 89 ± 3 ° C, air humidity 50 ± 5% RH, irradiation intensity 60~100 W / m ² 300 ~ 400 nm) for 500 hours. The grade of weathering is indicated by ΔE value. When the ΔE value is more than 5, the weather resistance of the polyetherester elastomer resin is deteriorated due to the action of oxygen, ozone and ultraviolet rays in the air, resulting in deterioration, coloration and cracking of the surface, It is difficult to apply to products other than the black series. Thus, more specifically, the weatherability grade ΔE must be less than 5.

(4) Heat deformation temperature

In accordance with ASTM D648, a 6.4 mm thick rod specimen was measured at a temperature at which a deformation of 1/100 inch occurred under a load of 18.6 kgf / cm 2 using a thermal deformation temperature measuring instrument.

(5) Particle size

The particle diameter range of the produced high-density polyethylene powders was expressed as a minimum particle diameter to a maximum particle diameter.

Modulus of elasticity
(N / mm < 2 & The tensile strength
(N / mm < 2 & Weatherability
(ΔE after 500 hours of light source measurement) Heat distortion temperature
(° C) Particle size
(탆) Example 1 4.1 2.6 4.6 102.1 1 to 2.4 Example 2 4.9 3.5 3.5 105.3 0.5 to 1 Comparative Example 1 3.5 0.8 9.3 101.5 3 to 6 Comparative Example 2 2.1 2.4 12.0 101.2 2.6 to 5.8 Comparative Example 3 3.3 2.1 18.5 100.1 3.1 to 5.2 Comparative Example 4 3.1 1.9 10.2 98.2 3.6 to 6.5 Comparative Example 5 No measurement (no high density polyethylene powder) Comparative Example 6 No measurement (no high density polyethylene powder)

As a result, as shown in Table 2, the tensile strength of the powder was remarkably low when the corona treatment was not performed as in Comparative Example 1. In the case of not using the elastomer resin as in Comparative Example 2, And it was found that when the acrylic graft resin was not used as in Comparative Example 3, the weather resistance was not good, and when 4,4'-bis (a, a-dimethylbenzyl-disphenylamine) The heat distortion temperature is low and the heat resistance is not good.

In Comparative Example 5, it was difficult to produce the powder itself because the process was carried out in the state where there was no liquid nitrogen gas during the production of the powder using the high-speed spin injection nozzle, and thus it was difficult to measure the physical properties. In Comparative Example 6, only the high-density polyethylene powder resin And then mixed with an elastomer resin, an acrylic graft resin and 4,4'-bis (a, a-dimethylbenzyl-disphenylamine) to prepare a molten resin, Therefore, it was difficult to measure the physical properties of the powders themselves.

On the other hand, in the case of Examples 1 and 2, powders having elasticity, tensile strength, weather resistance and heat distortion temperature (heat resistance) exhibit excellent overall results, and powder having a particle diameter smaller than that of the comparative example It can be seen that it is suitable as an asphalt reinforcing material.

Claims (12)

(S1) melting a high-density polyethylene (HDPE) resin and an elastomer resin to prepare a molten resin;
(S2) An acrylic graft resin and 4,4'-bis (a, a-dimethylbenzyldiphenylamine) [4,4'-bis (alpha, ;
(S3) preparing a high-density polyethylene powder by cryo-spraying the mixed resin using a high-speed spin injection nozzle under a liquid nitrogen gas; And
(S4) a step of corona spinning the high-density polyethylene powder. The method according to claim 1,
Wherein the step (S1) comprises melting 100 parts by weight of a high-density polyethylene resin and 2 to 3 parts by weight of an elastomer resin. The method according to claim 1,
Wherein the elastomer resin is one of the group consisting of a polyester-carbonate block copolymer, a polyurethane-ester block copolymer, a polyamide-ether block copolymer, and a mixture thereof. The method according to claim 1,
In step (S2), 1 to 10 parts by weight of an acryl-based graft resin and 100 parts by weight of 4,4'-bis (a, a-dimethylbenzyl-disphenylamine) 4, 4'-bis (alpha, alpha-dimethylbenzyldiphenylamine)] are mixed to prepare a mixed resin. The method according to claim 1,
Wherein the acrylic graft resin is grafted with 10 to 60% by weight of a (meth) acrylic rubber and 40 to 90% by weight of an aromatic vinyl compound-vinyl cyanide copolymer. 6. The method of claim 5,
Wherein the aromatic vinyl compound-cyanide vinyl compound copolymer is a copolymer of 60 to 80% by weight of an aromatic vinyl compound and 20 to 40% by weight of a vinyl cyanide compound. The method according to claim 1,
Wherein the high-speed rotation injection nozzle rotates at 1300 to 1700 rpm. The method according to claim 1,
And injecting air into the high-speed rotation injection nozzle together with the high-speed rotation injection nozzle. 8. The method of claim 7,
Wherein the pressure of air injected into the high-speed rotation injection nozzle is greater than 0 psi and less than 5 psi. The method according to claim 1,
Wherein the corona radiation treatment is performed under the condition of 50 to 80 W / m ² / min. The method according to claim 1,
Wherein the high-density polyethylene powder is spherical particles having a particle diameter of 0.5 to 5 占 퐉. The method according to claim 1,
Wherein the high-density polyethylene powder is for an asphalt reinforcement.