KR20150078004A - Microporous thermoplastic polymer resin foam with enhanced mechanical strength and foaming rate and the preparation thereof - Google Patents

Abstract

The present invention relates to a microporous thermoplastic polymeric resin foam having improved mechanical strength and foaming ratio, and a method for producing the same. According to various embodiments of the present invention, the viscosity of the thermoplastic polymer resin can be increased by adding a thickener to the thermoplastic polymer resin in order to solve the problem that the conventional thermoplastic polymer resin is difficult to foam with low viscosity, And can induce micropores. Therefore, it can be used not only for mass production of microporous foams, but also improves the mechanical strength of the foam, thereby achieving an effect that it can be usefully used in various molding products. have.

Description

Technical Field [0001] The present invention relates to a microporous thermoplastic polymer resin foam having improved mechanical strength and foaming ratio and a method for producing the same.

The present invention relates to a microporous thermoplastic polymeric resin foam having improved mechanical strength and foaming ratio, and a method for producing the same.

In general, polyethylene terephthalate (PET) is a typical material of saturated saturated polyester. It is a highly crystalline polymer and has high softening point, strength, chemical resistance, heat resistance, weather resistance and electrical insulation and is excellent in printing property, processability and transparency It is widely used in synthetic fibers, films, bottles, tire cords, tapes and packaging materials because it has the advantage of relatively low cost of resin.

In particular, PET foam is superior in heat resistance and physical properties compared with PS and PE foams widely used for building and packaging materials, and can be used for food containers, packaging containers, and building insulation materials. There is no induction of environmental hormone, which is very effective in improving the environment.

However, in the production of PET foam, the hydrolysis reaction of PET sharply changes the viscosity according to the temperature change to make foaming processing very difficult, and in order to produce the foam, the foam bubble cell grows and stabilizes under proper foaming environment However, PET is a highly crystalline polymer and it has been known that it is difficult to perform the foaming process due to the nature of the ball having a large change in melt viscosity near the melting temperature.

In order to solve the above problems, UOP, a company of Italy in the past, has introduced a monomer having a polyfunctional group in a PET polymerization reaction. However, in this case, the production cost is high and the product can not have a sufficient melt strength.

Another technique for producing PET foams is to use a polymer PET having an intrinsic viscosity of 0.95 dl / g or more to prepare a medium density foam using an inner nucleating agent and an N ₂ gas blowing agent. And foams are prepared using physical and chemical foaming agents. There is known a technique for manufacturing foam by reinforcing PET using a branching agent for PET. However, since the low viscosity of PET still causes foaming There is a demand for a method of producing a PET foam by a convenient foaming system which can be easily foamed.

SUMMARY OF THE INVENTION The present invention provides a microporous thermoplastic polymer resin foam having improved mechanical strength and a high foaming ratio, and a method for producing the same.

According to an exemplary aspect of the present invention,

(a) 100 parts by weight of a thermoplastic polymer resin

(b) 0.001-1 parts by weight supercritical fluid; And

(c) 0.5-10 parts by weight of a thickening agent.

According to another exemplary aspect of the present invention, there is provided a resin composition comprising (1) a resin obtained by mixing (a) 0.001-1 parts by weight of a supercritical fluid (b) and 0.5-10 parts by weight of a thickener (c) with respect to 100 parts by weight of a thermoplastic polymer resin Melting in a truezer to mix a thermoplastic polymer resin, a supercritical fluid, and a thickener;

(2) a step of discharging the molten mixture of step (1) into a die lip of an extrusion die to obtain a foam having micropores formed thereon.

According to various embodiments of the present invention, the viscosity of the thermoplastic polymer resin can be increased by adding a thickening agent to the thermoplastic polymer resin in order to solve the problem that the conventional thermoplastic polymer resin is difficult to foam with low viscosity, And can induce micropores. Therefore, it can be used not only for mass production of microporous foams but also improves the mechanical strength of the foam, thereby achieving an effect that it can be usefully used in various molding products. have.

Hereinafter, various aspects and various embodiments of the present invention will be described in more detail.

According to an aspect of the present invention,

(a) 100 parts by weight of a thermoplastic polymer resin in which a foaming nucleus agent is incorporated

(b) 0.001-1 parts by weight supercritical fluid; And

(c) 0.5 to 10 parts by weight of a thickening agent.

According to one embodiment of the present invention, the viscosity of the thermoplastic polymer resin can be increased by adding a thickening agent to the thermoplastic polymer resin in order to solve the problem of difficulty in foaming with a low viscosity in the conventional thermoplastic polymer resin, And can induce micropores. Therefore, it can be used not only for mass production of microporous foams but also for improving the mechanical strength of foams, and thus can be usefully used in various molding products.

When the thickener (c) is added in an amount of less than 0.5 part by weight based on 100 parts by weight of the thermoplastic polymer resin, the tensile strength may be lowered, and the viscosity of the PET may be lowered. There is a possibility that the effect of improving the performance is insufficient. In addition, when the amount is more than 10 parts by weight, the non-melting phenomenon occurs due to an excessive increase of the viscosity, so that the discharge of the foaming resin from the die is unstable and the foaming rate may be lowered.

On the other hand, when the (b) supercritical fluid is added in an amount of less than 0.001 part by weight based on 100 parts by weight of the thermoplastic polymer resin (a), a sufficient foaming ratio may not be obtained. The foam surface may have defective appearance problems such as blisters.

In one embodiment of the present invention, the thermoplastic polymer resin (a) is at least one selected from the group consisting of polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polycarbonate (PC), polystyrene (PS), acrylic polymer At least one member selected from the group consisting of polyamide (PAm), acrylonitrile-butadiene-styrene copolymer (ABS), polyvinyl chloride (PVC), polyethylene (PE), polypropylene (PP) , And blends or copolymers of two or more thereof.

In another embodiment of the present invention, (b) the supercritical fluid is at least one selected from nitrogen, carbon dioxide, argon, neon, and helium.

In another embodiment of the present invention, the (c) thickening agent is a substance having three or more hydroxyl or carboxyl groups and may be selected from the group consisting of trimethylpropanol, glycerin, pentaerythritol, trimellitic acid hydride, pyromellitic dianhydride Hydride, and boronic acid, or a material having an epoxy reactive group, which is characterized by being at least one selected from glycidyl acrylate and clicidyl methacrylate.

In another embodiment of the present invention, the (a) thermoplastic polymer resin further comprises a foaming nucleating agent.

The foam nucleating agent may be added in an amount of 0.01 to 40 parts by weight, preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the thermoplastic polymer resin (a).

The foam nucleating agent may be at least one kind of inorganic fine powder selected from talc, CaCO ₃ , SiO ₂ , MgO and ZnO. When the inorganic fine powder having a particle size of 50 μm or less is used, Can be manufactured.

In another embodiment of the present invention, the pore size of the microporous thermoplastic polymeric resin foam is 0.5-300 μm, and the tensile strength of the microporous thermoplastic polymeric resin foam is 20-50 N / mm ² .

According to an embodiment of the present invention, the light maximizes diffuse reflection through the microfluidizer and the interface. Since the microporous thermoplastic polymer resin foam of the present invention has a large number of micropores, the reflection sheet for LCD backlight or the reflection sheet for LED illumination It can be usefully used, and can be used as an insulating material, a building material, a heat insulating material, a soundproofing material, a packaging material and the like.

According to another aspect of the present invention,

(1) A resin obtained by mixing (a) 0.001-1 parts by weight of (b) supercritical fluid and 0.5-10 parts by weight of (c) a thickener with respect to 100 parts by weight of a thermoplastic polymer resin is melted in an extruder to form a thermoplastic polymer resin, Mixing the supercritical fluid and the thickener;

(2) a step of discharging the molten mixture of step (1) into a die lip of an extrusion die to obtain a foam having micropores formed therein, the method comprising the steps of:

The thermoplastic polymer resin (a) is at least one selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, biodegradable polyester, and polyolefin-based polymer resin,

The supercritical fluid (b) is at least one selected from nitrogen, carbon dioxide, argon, neon, and helium,

The (c) thickener may be at least one selected from the group consisting of trimethyl propanol, glycerin, pentaerythritol, trimellitic acid hydride, pyromellitic dianhydride, boronic acid, glycidyl acrylate and clicidyl methacrylate Wherein the microporous thermoplastic polymeric resin foam is produced by a method comprising the steps of:

In one embodiment of the present invention, the temperature in the extruder during the melting in the step (1) is 200-300 ° C.

The extruder used in the step (1) is a device for heating and melting the raw polymer, and the raw polymer can be completely melted by adjusting the temperature and pressure in the extruder.

In another embodiment of the present invention, the extrusion die passing speed of the molten mixture in the step (3) is 0.5-30 m / min, and the extrusion die has a discharge pressure of 20-200 bar.

According to an embodiment of the present invention, since the pores grow due to the pressure difference between the inside of the die and the inside of the die, the discharge pressure is an important condition for controlling pore growth. When the discharge pressure of the extrusion die is less than 20 bar There may be a problem that the foaming rate is lowered and the growth efficiency of the foam is deteriorated. If it is more than 200 bar, the foam may be excessively expanded while being discharged from the inside of the die, and the sheet thickness and shape may become uneven.

In another embodiment of the present invention, the extrusion die of step (3) is characterized by being an extruded T-die.

In yet another embodiment of the present invention, the thermoplastic polymer resin (a) further comprises a foaming nucleating agent.

The foam nucleating agent may be added in an amount of 0.01 to 40 parts by weight, preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the thermoplastic polymer resin (a).

The foam nucleating agent may be at least one kind of inorganic fine powder selected from talc, CaCO ₃ , SiO ₂ , MgO and ZnO, and the foam nucleus has a particle size of 50 μm or less.

Hereinafter, the present invention will be described in more detail with reference to Examples and the like, but the scope and content of the present invention can not be construed to be limited or limited by the following Examples. In addition, it is apparent that, based on the teachings of the present invention including the following examples, those skilled in the art can easily carry out the present invention in which experimental results are not specifically shown.

Example  One

To 100 parts by weight of PET was added a mixture of 3 parts by weight of talc and 1 part by weight of a thickener, and 0.2 parts by weight of a nitrogen gas was added at 250 DEG C and 80 bar. Then, the mixture was extruded through a T-die through an extruder A foam was prepared.

Example  2

The foam was prepared in the same manner as in Example 1, except that 2 parts by weight of the thickener was used instead of 1 part by weight of the thickener.

Comparative Example  One

A foam was prepared in the same manner as in Example 1 except that a thickener was not added instead of 1 part by weight of a thickener.

Comparative Example  2

A foam was prepared in the same manner as in Example 1 except that 12 parts by weight of a thickener was added instead of 1 part by weight of a thickener.

Table 1 below shows the die pressure, foaming ratio and tensile strength according to the amount of the thickener added in Examples 1 and 2 and Comparative Examples 1 and 2.

Amount of thickener added
(Parts by weight) Die pressure
(bar) Foaming rate
(%) The tensile strength
(N / mm ² ) Example 1 One 83 53 21 Example 2 2 110 60 29 Comparative Example 1 0 61 47 15 Comparative Example 2 12 250 12 -

As shown in Table 1, the foams of Examples 1 and 2 according to the present invention have excellent foaming ratios as the viscosity of the PET resin increases, can control the foaming rate by controlling the addition amount of the thickener, Because of its excellent strength, it can be usefully used in various molding products.

Claims (17)

(a) 100 parts by weight of a thermoplastic polymer resin
(b) 0.001-1 parts by weight supercritical fluid; And
(c) 0.5-10 parts by weight of a thickener.
The method according to claim 1,
The thermoplastic polymer resin (a) may be at least one selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, polycarbonate, polystyrene, acrylic resin, polyamide, acrylonitrile-butadiene-styrene copolymer, polyvinyl chloride, polyethylene, Wherein the microporous thermoplastic polymeric resin foam is at least one selected from the group consisting of polyvinyl alcohol and polyvinyl alcohol.
The method according to claim 1,
(B) the supercritical fluid is at least one selected from nitrogen, carbon dioxide, argon, neon, and helium.
The method according to claim 1,
The (c) thickener may be at least one selected from the group consisting of trimethyl propanol, glycerin, pentaerythritol, trimellitic acid hydride, pyromellitic dianhydride, boronic acid, glycidyl acrylate and clicidyl methacrylate Wherein the microporous thermoplastic polymer resin foam is a thermoplastic resin.
The method according to claim 1,
Wherein the thermoplastic polymer resin (a) further comprises a foaming nucleating agent.
6. The method of claim 5,
Wherein the foam nucleating agent is added in an amount of 0.01 to 40 parts by weight based on 100 parts by weight of the thermoplastic polymer resin (a).
6. The method of claim 5,
Wherein the foaming nucleating agent is at least one selected from the group consisting of talc, CaCO ₃ , SiO ₂ , MgO, and ZnO,
Wherein the foam nucleus has a particle size of 50 mu m or less.
The method according to claim 1,
Wherein the microporous thermoplastic polymeric resin foam has a pore size of 0.5 to 300 占 퐉.
The method according to claim 1,
Wherein the microporous thermoplastic polymer resin foam has a tensile strength of 20-50 N / mm ² .
(1) A resin obtained by mixing (a) 1 to 5 parts by weight of a supercritical fluid (b) and 0.5 to 10 parts by weight of a thickener (c) with respect to 100 parts by weight of a thermoplastic polymer resin is melted in an extruder to form a thermoplastic polymer resin, Mixing the supercritical fluid and the thickener;
(2) a step of discharging the molten mixture of step (1) into a die lip of an extrusion die to obtain a foam having micropores formed therein, the method comprising the steps of:
The thermoplastic polymer resin (a) is a thermoplastic polymer resin which is obtained by copolymerizing (a) a thermoplastic polymer resin such as polyethylene terephthalate, polybutylene terephthalate, polycarbonate, polystyrene, acrylic resin, polyamide, acrylonitrile-butadiene- Polyethylene, polypropylene, and fluororesin.
The supercritical fluid (b) is at least one selected from nitrogen, carbon dioxide, argon, neon, and helium,
The (c) thickener may be at least one selected from the group consisting of trimethyl propanol, glycerin, pentaerythritol, trimellitic acid hydride, pyromellitic dianhydride, boronic acid, glycidyl acrylate and clicidyl methacrylate Wherein the microporous thermoplastic polymeric resin foam is a polyolefin resin.
11. The method of claim 10,
Wherein the extruder has a temperature in the range of 200-300 DEG C during the melting in the step (1). ≪ RTI ID = 0.0 > 11. < / RTI >
11. The method of claim 10,
Wherein the extrusion die passing speed of the molten mixture in step (2) is 0.5-30 m / min.
11. The method of claim 10,
Wherein the discharge pressure of the extrusion die is 20-200 bar in the step (2).
11. The method of claim 10,
Wherein the extrusion die of step (2) is an extruded T-die.
11. The method of claim 10,
Wherein the thermoplastic polymer resin (a) further comprises a foaming nucleating agent. The method for producing a microporous thermoplastic polymer resin foam according to claim 1,
16. The method of claim 15,
Wherein the foam nucleating agent is added in an amount of 0.01 to 40 parts by weight based on 100 parts by weight of the thermoplastic polymer resin (a).
16. The method of claim 15,
Wherein the foaming nucleating agent is at least one selected from the group consisting of talc, CaCO ₃ , SiO ₂ , MgO, and ZnO,
Wherein the foam nucleus has a particle size of 50 m or less. ≪ RTI ID = 0.0 > 21. < / RTI >