KR100787004B1 - The method of manufacturing polyethylene firing fabric and the polyethylene firing fabric manufactured thereby - Google Patents

Abstract

A method for preparing polyethylene foamed fabrics and polyethylene foamed fabrics prepared by the method are provided to reduce time and space by omitting a maturation process and to prevent the contamination of product due to a cell stabilizer. A method for preparing polyethylene foamed fabrics comprises the steps of adding a nucleating agent to polyethylene, and heating it to prepare a molten polymer; mixing the molten polymer with a foaming agent to form a foaming gel; cooling the foaming gel at an optimum foaming temperature; and extruding the foaming gel, wherein the foaming agent is isobutane or 1,1-difluoroethane, and the process is carried out without using a cell stabilizer. Preferably the optimum foaming temperature is 93-100 deg.C.

Description

The manufacturing method of polyethylene foam fabric and the polyethylene foam fabric manufactured by the above-mentioned method.

Polyethylene is easy to process and possesses excellent physical properties such as chemical resistance, hygiene stability, insulation, impact strength, etc., so that various processing methods such as film, extrusion coating, foaming, injection molding, etc. are applied to agriculture, food packaging, general packaging, building supplies, various It is widely used in various applications such as parts, sports and household goods.

Since it is applied to various uses as described above, the product properties required for each use are different, and therefore, various additives are used to satisfy the required properties of each use that cannot be satisfied only with the properties of polyethylene itself. However, additives used often cause unexpected problems due to surface migration.

Foamed polyethylene has excellent impact shock resistance, heat insulation, chemical resistance and moisture resistance, and is widely used in various cushioning packaging materials, building insulation materials, and various forms of sports / household goods.

Extrusion foam molding process of polyethylene is divided into crosslinking foaming and non-crosslinking foaming process.Because cross-linking foaming requires large-scale equipment investment, only a few companies in Korea produce butane gas in blowing agent. Polyethylene foam sheet is produced by using a cross-linking extrusion foaming process.

In the non-crosslinked extrusion foaming method of polyethylene, polyethylene resin and additives (mainly nucleating agents, pigments, etc.) are first introduced into a hopper and kneaded in an extruder, which serves as a blowing agent at the extruder stop part (mainly butane or propane) and a foam cell stabilizer. The surfactant is injected. The blowing agent and various additives thus injected exit the die in a state of being well kneaded with the polyethylene resin under high pressure in the extruder, and as a result of the external pressure being lowered, the foaming agent expands and a foaming cell is formed.

That is, the conventional foamed polyethylene fabric was formed through the following non-crosslinked extrusion foaming process steps:

① Naturally flowing polyethylene raw material into the machine,

② inserting the nucleating agent into the hopper,

③ the step of moving to the scoop while maintaining the temperature at 150 ~ 180 ℃,

④ move the temperature up to 230 ℃ while making a complete liquid,

⑤ injecting the cell stabilizer,

⑥ injecting the blowing agent,

⑦ mixing the gas, cell stabilizer and blowing agent by rotating the screw;

⑧ moving the hot mixture toward the projection while gradually cooling the cooling mixture from about 93 ° C. to about 100 ° C.,

⑨ creating a thickness and fabric width using a die at the protrusion,

⑩ making the roll state while blowing cold air and cooling air, and

가스 replacing the gas used as blowing agent with air in a aging room at about 20-30 ° C. for about 7 days.

The blowing agent used in the above process is an additive for preparing a porous foam by blending with a polymer, and butane or propane have been mainly used in the conventional non-crosslinking extrusion foaming process. These blowing agents store the liquefied gas in a safe tank of 5 kg / cm ² internal pressure and maintain a constant pressure of 15 kg / cm ² through the primary pressure pump to 150 kg / cm ² again through the secondary boost pump. Create a second high-pressure state and feed it into the machine. The gas is a gas that is well mixed with the polyethylene raw material and helps to form about 40 times secondary foaming of the liquid raw material mixed with the cell stabilizer and the nucleating agent. The amount of blowing agent used in the conventional manner is from about 9% to about 12% by weight, when used in less than 9% by weight, there is a problem that the expanded polyester fabric is deformed or excessively necessary raw materials, used in excess of 12% by weight When the popping phenomenon appeared in the part and there was a problem that a lot of bone is formed by over-foaming.

In addition, additives used in the crosslinking extrusion foaming process include a nucleating agent and a cell control agent.

The nucleating agent acts as a nucleus to allow bubbles to grow, and the addition of the nucleating agent makes it possible to make the foaming cell more uniform and smaller. The amount of nucleating agent used in the conventional method is about 0.8% to about 1.3% by weight, when the content is less than 0.8% by weight, there is a problem that the cell is large and the contents, and when added in excess of 1.3% by weight, the fabric has a lot of bones There is a problem of lightening. Examples of nucleating agents include clay, talc, silica and the like.

The surfactant used as a cell stabilizer, like soap used in soap bubbles, serves to lower the surface tension of polyethylene so that the cell can be stably formed without breaking even if the cell expands rapidly. In this regard, the foamed fabric is mixed with highly flammable propane gas when it is produced in order to maintain the thickness and width during the maturation period in the foaming state, and the friction and the static electricity generated in the die to cause a fire Therefore, the cell stabilizer was an essential mixture that must be added when using propane gas or the like. The amount of cell stabilizer used in the conventional method is about 0.8% to about 1.2% by weight, and when added below 0.8% by weight, there is a problem that foam is retracted and there is a high risk of fire, and when added in excess of 1.2% by weight. There was a liquid problem on the surface and slippery problem. As a cell stabilizer, GMS (Glycerine Monostearate) is mainly used. GMS is a substance that turns into a liquid from a solid state when heated at 68 ° C. It is used by melting an electric heater in a tank of 110 ° C high temperature, and is injected into the machine through a pressure pump in a liquid state.

It is because of the risk of fire that the polyethylene foam fabric finally prepared in the process is replaced with air in the aging chamber at about 20 to 30 ° C. for about seven days.

Recently, when the LCD TV screen was packaged with conventional polyethylene foam paper foamed with butane or propane gas, it was good at room temperature. However, when the container was moved or stored for a long time, it was found that the surface of the LCD panel was stained. Analysis of the material confirmed that the cell stabilizer is a paraffin-based additive. However, when foaming polyethylene using a gas (butane or propane) serving as a conventional blowing agent, the use of a cell stabilizer is not used together, the risk of fire increases, and the fabric is retracted to cause a failure.

Accordingly, it is an object of the present invention to provide a method for producing a high quality foamed polyethylene without using a cell stabilizer in the foaming process.

This object of the present invention can be achieved by using isobutane or 1,1-difluoroethane in place of butane or propane, which is a gas which is conventionally used as a blowing agent.

The present invention comprises the steps of adding a nucleating agent to the polyethylene raw material and heating to form a molten polymer material (a), incorporating a blowing agent into the molten polymer material (b) to form a foam gel, foaming gel to the optimum foaming temperature A process for producing a polyethylene foam fabric comprising the step of (c) cooling and extruding the expandable gel through a die, wherein the blowing agent is isobutane or 1,1-difluoroethane and the cell stabilizer is It relates to a method for producing a polyethylene foam fabric characterized in that it is not used.

The present invention relates to a process wherein said blowing agent is isobutane.

The present invention relates to a process wherein said blowing agent is 1,1-difluoroethane.

The present invention relates to a process wherein the amount of said nucleating agent is from about 1.8% to about 2.5% by weight.

The present invention relates to a method wherein the amount of said nucleating agent is about 2% by weight.

The present invention relates to a process wherein said optimum foaming temperature is from about 93 ° C to about 100 ° C.

The present invention relates to a polyethylene foam fabric produced by the above method.

More specifically, the process steps of the present invention go through the following steps:

① Naturally flowing polyethylene raw material into the machine,

② inserting the nucleating agent into the hopper,

③ the step of moving to the scoop while maintaining the temperature at 150 ~ 180 ℃,

④ move the temperature up to 230 ℃ while making a complete liquid,

⑤ injecting isobutane or 1,1-difluoroethane as blowing agent,

⑥ mixing the gas and the blowing agent by rotating the scoop,

⑦ moving the high temperature mixture toward the projection while gradually cooling the cooling portion from about 93 ° C. to about 100 ° C.,

⑧ Create the thickness and fabric width using the die at the protrusion,

⑨ Create a rolled state while blowing cold air and cooling air.

The nucleating agent of the present invention may be any conventionally used nucleating agent, for example, clay, talc, silica and the like can be used. In the present invention, the addition amount of the nucleating agent is preferably about 1.8% by weight to about 2.5% by weight, and when added in less than 1.8% by weight, there is a problem in that the cell becomes large and the contents, and when added in excess of 2.5% by weight, There is a problem that is much lighter. More preferably about 2% to about 2.5% by weight, most preferably about 2% by weight is used.

Isobutane or 1,1-difluoroethane, which is a blowing agent of the present invention, is preferably used at about 9% by weight to about 13% by weight, more preferably at about 12% by weight. When used in less than 9% by weight, there is a problem that the raw material is over-injected, when used in excess of 13% by weight, there is a problem that a lot of bone, over-foaming occurs.

On the other hand, the cooling unit is a part for cooling to 100 ℃ in a state heated to 200 ℃ or more by an electric heater, it is heated by an automatic device, or cold cold water flows, and when heated, the water is blocked and the temperature of the heater rises In case of cooling, the heater temperature is cut off and the cold water flows to cool.

In addition, the die to control the pressure at the outlet to make the thickness of the fabric, the size of the circular shape to maintain the width and make the foam fabric. The foaming material coming out of the die is about 93 ° C to about 100 ° C, and the foaming material is gradually cooled by natural wind so that the temperature of the fabric winding time is about 20-30 ° C.

EXAMPLE

The following examples are exemplary only and are not intended to limit the scope of the invention. As used herein, the weight percent refers to 100% by weight of the total weight of the additive.

Comparative example  One

Of the polyethylene raw material, 88% by weight of LDPE 5321, purchased from Hanyang Petrochemical, was naturally flowed into the machine, and then charged into a 1% by weight hopper of THY 1655 purchased from Taehae Young as a nucleating agent. Move to Sukuru while maintaining the temperature at 150 ~ 180 ℃, move the temperature up to 230 ℃ to make a complete liquid, and melt 1% by weight of GMS as a cell stabilizer using an electric heater in a 110 ℃ high temperature tank. After that, it was introduced into the machine through a pressure pump in a liquid state. Then, the propane gas was maintained at a constant pressure of about 12 kg / cm ² through the primary pressure pump as a blowing agent, and a second high pressure state was again generated at about 150 kg / cm ² through the secondary boost pump, and 10 wt% After injection, the scoop was rotated to mix the polyethylene, cell stabilizer, and blowing agent, and the hot mixture was moved toward the protrusion while slowly cooling to 100 ° C. in the cooling section. The dies at the protrusions were used to create the thickness and width of the fabric, rolled with cold air and air cooled. Aging at room temperature for 7 days.

Comparative example  2

A polyethylene foam fabric was prepared in the same manner as in Comparative Example 1 except that 0.8 wt% of GMS was used.

Comparative example  3

A polyethylene foam fabric was prepared in the same manner as in Comparative Example 1 except that no GMS was used.

Example  One

After the 86% by weight of LDPE 5321 purchased from Hanyang Petrochemical was naturally flowed into the machine as a polyethylene raw material, THY 1655 was added to a 2% by weight hopper as a nucleating agent. The train while maintaining the temperature at 150 ~ 180 ℃ Surgical ruro move, move, making the temperature to complete the liquid up to 230 ℃ and was the (one R-600 ^® purchased from Firstec) iso-butane as a blowing agent injected into 12 weight% . The scoop was rotated to mix the polyethylene and blowing agent and the hot mixture was moved towards the protrusions while slowly cooling to 100 ° C. Dies were used on the protrusions to create thickness and fabric width, rolled with cold air and air cooled. Observation was made while aging in a aging room at room temperature.

Example  2

A polyethylene foam fabric in the same manner as in Example 1 except that the (one R-152 ^® purchased from Firstec) ethane instead of isobutane gas-difluoro was prepared as a blowing agent.

Comparative example  4

Except that (a R-12 ^® purchased from Firstec) isobutane gas instead of CCl ₂ F ₂ as the blowing agent and was prepared and the polyethylene foam fabric in the same manner as in Example 1.

Comparative example  5

As a blowing agent to prepare a foamed polyethylene fabric in the same manner as in Example 1 except that the (one R-22 ^® purchased from Firstec) CHClF ₂ gas instead of isobutane.

result

As a result of manufacturing the polyethylene foam fabric by the above method, the polyethylene foam fabric produced by Comparative Example 1 caused staining on the surface of the precision product. In addition, the polyethylene foam fabric produced by Comparative Example 2 was often broken fabric, the fabric was lost strength, the thickness of the fabric quickly became thin, did not return to its original shape even after the aging period. In the case of Comparative Example 3 in which no GMS was added, a fire occurred, the thickness of the fabric was rolled up to a roll, and it did not return to its original shape even after aging. In Comparative Examples 4 and 5, no foam cells were formed.

On the other hand, the polyethylene foam fabric formed by Examples 1 and 2 is a fabric that can be used to form a cell little by little after two days in the aging room.

The present invention provides a method for producing a high-quality foam polyethylene without using a cell stabilizer in the foaming process, there is no need to store dangerous gases for a long time, and do not need to be aged for 7 days in the aging room, the time to use the fabric It saves and saves space for aging storage for 7 days. In addition, there is an effect that can prevent the fire caused by the gas during production or ripening, and the mixture is reduced, it is environmentally friendly to human body. In addition, the present invention has a remarkable effect of not using the cell stabilizer above all, so that the cell stabilizer does not adhere to the product.

Claims (7)

A process for producing a polyethylene foam fabric comprising: a foaming agent is isobutane or 1,1-difluoroethane and no cell stabilizer is used; (a) adding a nucleating agent to polyethylene raw material followed by heating to form a molten polymeric material, (b) incorporating a blowing agent into the molten polymeric material to form a foamable gel, (c) cooling the foamable gel to an optimal foaming temperature, and (d) extruding the expandable gel through the die. The method of claim 1 wherein the blowing agent is isobutane. The method of claim 1 wherein the blowing agent is 1,1-difluoroethane. The method of claim 1 wherein the amount of nucleating agent is from 1.8 wt% to 2.5 wt%. The method of claim 4 wherein the amount of nucleating agent is 2% by weight. The process according to claim 1, wherein the optimum foaming temperature is between 93 ° C and 100 ° C. Polyethylene foam fabric produced by the method according to any one of claims 1 to 6.