KR102295005B1 - Resin composition for preparing sheet with adhesive property - Google Patents

Abstract

Disclosed is a resin composition for a waterproof sheet that has excellent tensile strength and elongation and excellent adhesion, which can be applied to the manufacture of large sheets. The present invention provides a resin composition for a waterproof sheet comprising a thermoplastic resin having a density of 0.9 g/cc or less, low-density polyethylene, and ethylene vinyl acetate.

Description

Resin composition for a waterproof sheet excellent in adhesiveness {Resin composition for preparing sheet with adhesive property}

The present invention relates to a resin composition for a waterproof sheet, and more particularly, to a resin composition for a waterproof sheet that can be applied to the manufacture of a large sheet.

Changes in precipitation are also being significantly affected by climate change. Accordingly, the importance of waterproofing of buildings and social infrastructure (tunnels, water/sewage structures, etc.) is newly recognized. The most important item among these waterproof properties is long-term durability and stability, and various types of waterproofing materials are used to satisfy the requirements.

Common waterproof materials include asphalt, cement, synthetic polymer sheets, paint films, and metal plates. Among them, the synthetic polymer sheet has good enough cold resistance, water resistance, and fatigue resistance, has little effect on temperature change, and is a preferred material because it can implement various colors. The waterproof sheet for embedding is manufactured by mixing a polyethylene-based resin, and may be used by appropriately adjusting the ratio of the components according to the required physical properties.

Since it is impossible to form a sheet with a width greater than a certain size, several sheets are attached to each other. However, when the adhesion between the sheets is insufficient, damage may occur or physical properties may be deteriorated due to an external environment. In order to solve this problem in the industrial field, the adhesion test is performed by blowing high-temperature and high-pressure air into the sheet with both ends attached. In order to increase adhesion, a technology has been developed to prevent problems from occurring in the construction of sheet waterproofing materials, such as using materials with functional end groups or using various materials in a composite or multi-layered manner, but the exact improvement method is not mentioned. can't

In order to solve this problem, Korean Patent No. 10-0580574 discloses an integrated dry-type composite waterproofing material that can be easily installed on site without applying and curing the waterproofing material, but does not mention the increase in adhesion. .

An object of the present invention is to provide a resin composition for a waterproof sheet that is excellent in tensile strength and elongation and excellent in adhesion, which can be applied to the manufacture of large sheets.

In order to solve the above problems, the present invention provides a resin composition for a waterproof sheet comprising a thermoplastic resin having a density of 0.9 g/cc or less, low-density polyethylene, and ethylene vinyl acetate.

In addition, the thermoplastic resin includes ultra-low-density polyethylene (ULDPE) having a density of less than 0.8 g/cc, ultra-low-density polyethylene (VLDPE) having a density of 0.8 to 0.9 g/cc, ethylene-octene rubber (EOR) and ethylene-butene copolymer (EBR). ) provides a resin composition for a waterproof sheet, characterized in that at least one selected from the group consisting of.

In addition, the thermoplastic resin provides a resin composition for a waterproof sheet, characterized in that the weight average molecular weight is 80,000 or more.

In addition, the low-density polyethylene provides a resin composition for a waterproof sheet, characterized in that the linear low-density polyethylene or branched low-density polyethylene.

In addition, the content of the thermoplastic resin is 5 to 20% by weight, the content of the low density polyethylene is 30 to 60% by weight, the resin composition for a waterproof sheet, characterized in that the content of the ethylene vinyl acetate is 20 to 50% by weight provides

In addition, there is provided a resin composition for a waterproof sheet, characterized in that the component having a melting point of 95° C. or less in the resin composition for a waterproof sheet is 5 to 40% by weight of the total resin composition for a waterproof sheet.

In addition, the resin composition has a tensile strength (ASTM D 638) of 15 MPa or more, an elongation (ASTM D 638) of 650% or more, and maintains adhesion in an adhesion test according to the following method for a waterproof sheet A resin composition is provided.

[Adhesive test method]

Adhesive the two sheets made of the resin composition and blow air at 600° C. and 2 bar to check whether the adhesiveness is maintained.

In addition, there is provided a sheet made of the resin composition.

As a resin composition for a waterproof sheet, by combining a thermoplastic resin having a density in a specific range, low-density polyethylene, and ethylene vinyl acetate, it has excellent tensile strength and elongation and excellent adhesion to provide a resin composition for a waterproof sheet that can be applied to the manufacture of large sheets. can provide

Hereinafter, preferred embodiments of the present invention will be described in detail. In describing the present invention, if it is determined that a detailed description of a related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted. Throughout the specification, when a part "includes" a certain component, it means that other components may be further included, rather than excluding other components, unless otherwise stated.

The present inventors need a resin composition for a waterproof sheet excellent in adhesion while having a conventional tensile strength and elongation at a usable level. It has been found that when the thermoplastic resin, low-density polyethylene and ethylene vinyl acetate are included, the tensile strength and elongation are excellent while the adhesion is dramatically improved, leading to the present invention.

Accordingly, the present invention discloses a resin composition for a waterproof sheet comprising a thermoplastic resin having a density of 0.9 g/cc or less, low density polyethylene, and ethylene vinyl acetate.

Hereinafter, each component of the resin composition according to the present invention will be described in more detail.

(A) a thermoplastic resin having a density of 0.9 g/cc or less

The thermoplastic resin used in the present invention has a density of 0.9 g/cc or less, and by employing a thermoplastic resin having a lower density than that of a generally used low-density thermoplastic resin, the adhesiveness of the sheet prepared from the final resin composition, particularly the low-temperature adhesive property, is improved. make it possible

As such a thermoplastic resin, ultra-low-density polyethylene (ULDPE) with a density of 0.8 g/cc or less, ultra-low-density polyethylene (VLDPE) with a density of 0.8 to 0.9 g/cc, ethylene-octene rubber (EOR), ethylene-butene copolymer (EBR) etc. can be used, and thermoplastic resins that can exhibit similar properties can also be mixed. In the case of ethylene-octene rubber (EOR) and ethylene-butene copolymer (EBR), even though they are elastic materials, if they have a low density at a certain level, they can be converted into sheets through a specific combination with low-density polyethylene and ethylene vinyl acetate, which will be described later. It was confirmed for the first time by the present inventors that the adhesive properties can be improved during manufacturing, and it is expected that it will contribute to the expansion of application of the component to various materials.

The physical properties of the waterproof sheet currently required in the industrial field are the tensile strength of 25 MPa or more and the elongation of 700% or more. When the thermoplastic resin is not included, the tensile strength, elongation, and adhesive properties of the sheet made of the final resin composition are significantly reduced.

In addition, the thermoplastic resin having a density of 0.9 g/cc or less according to an embodiment of the present invention may have a weight average molecular weight of 80,000 or more, preferably 80,000 to 500,000, more preferably 85,000 to 300,000. When the weight average molecular weight is less than 80,000, the tensile strength may be lowered, and the adhesive properties may be slightly lowered.

Meanwhile, the content of the thermoplastic resin may be 5 to 20% by weight, preferably 7 to 18% by weight, and more preferably 8 to 16% by weight. When the content of the thermoplastic resin is less than 5% by weight, tensile strength, elongation and adhesive properties may be reduced, and if it exceeds 20% by weight, a yield point may not appear and the tensile strength may be slightly lowered.

(B) low density polyethylene

The low-density polyethylene used in the present invention is a material for expressing basic characteristics of the molded article, for example, strength, toughness, etc., and low-density polyethylene used for sheets may be used without limitation, for example, linear low-density polyethylene or branched polyethylene. Type low density polyethylene can be used. The linear low-density polyethylene or branched low-density polyethylene has a density of 0.915 to 0.925 g/cc, which is slightly greater than that of the thermoplastic resin.

In the final resin composition, when a sheet is manufactured using a resin composition that does not contain the low-density polyethylene, the desired softness, strength, and elongation properties cannot be satisfied.

Meanwhile, the content of the low-density polyethylene may be 30 to 60% by weight, preferably 35 to 60% by weight, and more preferably 40 to 55% by weight. Considering the content range of the thermoplastic resin and ethylene vinyl acetate to be described later, when the content of the low-density polyethylene is out of the range of 30 to 60% by weight, the physical property balance of the final resin composition is not balanced, so that the desired tensile strength, elongation and adhesive properties are obtained. Implementation can be difficult.

(C) ethylene vinyl acetate (EVA)

Ethylene vinyl acetate used in the present invention is a copolymer of ethylene and vinyl acetate (VA), and has excellent transparency, flexibility, and low-temperature brittleness. It is used as a resin and is attracting attention as an alternative material for polyvinyl chloride (PVC) due to its excellent ductility. Since ethylene is non-polar while vinyl acetate is a material containing oxygen atoms, it is polar, so ethylene vinyl acetate resin is well mixed with polar resins as well as non-polar resins, and has the property of being compatible with various kinds of chemical additives. have.

The physical properties of ethylene vinyl acetate may be variously determined according to molecular weight, vinyl acetate content, and polymerization degree. As the molecular weight of ethylene vinyl acetate is increased, toughness, plasticity and impact resistance can be improved, and moldability and surface gloss are reduced. On the other hand, as the content of vinyl acetate decreases, its properties are similar to those of polyethylene (PE), and as the content increases, compatibility with polymers or plasticizers with different density, rubber elasticity, and flexibility is improved, and the softening temperature is lowered. Usually, the vinyl acetate content is 7 to 60% by weight, and preferably 25 to 50% by weight.

However, in the present invention, when only ethylene vinyl acetate is further included in the thermoplastic resin without using the low-density polyethylene, waterproof properties may be reduced, and even if the low-density polyethylene is used in the thermoplastic resin, the ethylene vinyl acetate content is at a certain level. If it does not meet the required adhesive properties, it may be difficult to achieve the desired adhesive properties even if the waterproof properties are maintained. In addition, when the molecular weight of the ethylene vinyl acetate is low, adhesiveness may increase, but sheet molding may be difficult.

Therefore, in the present invention, by including the aforementioned low-density polyethylene together with the ethylene vinyl acetate in a specific content range in the thermoplastic resin having a certain level of density, both adhesiveness and waterproof properties can be implemented at an excellent level when manufacturing a sheet with the final resin composition, , the desired tensile strength and elongation properties can also be realized.

On the other hand, the content of the ethylene vinyl acetate may be 20 to 50% by weight, preferably 25 to 47% by weight, more preferably 30 to 45% by weight. When the content of the ethylene vinyl acetate is less than 20% by weight, it may be difficult to realize the desired tensile strength, elongation and adhesive properties in consideration of the content range of the thermoplastic resin and low density polyethylene, and when it exceeds 50% by weight, waterproof properties and elongation may be reduced.

According to the present invention, the resin composition in which a thermoplastic resin having a specific density range and low density polyethylene and ethylene vinyl acetate are combined in a specific content range has excellent tensile strength and elongation, and excellent adhesive properties and waterproof properties, so that it can be applied to the manufacture of large sheets. As a result of analyzing the thermal properties using a differential scanning calorimeter for the resin composition of these properties, the component having a melting point of 95° C. or less is 5 to 40 wt % of the total resin composition, preferably It was found to be preferably 10 to 30% by weight, more preferably 20 to 30% by weight. From this, it was confirmed that there is a range that satisfies specific thermal properties for realizing the desired physical properties in the present invention.

Furthermore, the resin composition satisfying the above thermal properties has waterproof properties, has excellent tensile strength and elongation, and exhibits excellent adhesion properties. Specifically, the resin composition according to the present invention has a tensile strength (ASTM D 638) of 15 MPa or more, preferably 20 MPa or more, elongation (ASTM D 638) is 650% or more, preferably 700% or more, and has a property of maintaining adhesion in an adhesion test according to the following method.

[Adhesive test method]

The two sheets made of the resin composition were adhered at 170° C. and 50 bar conditions for 1 minute, and air at 600° C. and 2 bar was blown to check whether the adhesiveness was maintained.

The resin composition for a waterproof sheet of the present invention may further include one or more conventional additives known in the art as other additives other than the above components, such as antioxidants, neutralizers, UV stabilizers, antistatic agents, and the like. At this time, each additive may be included in the range of 0.01 to 1 part by weight based on 100 parts by weight of the resin composition of the present invention.

The preparation of the resin composition for a waterproof sheet according to the present invention as described above may be performed according to a conventional method, for example, after mixing the components, a single screw extruder, a multi screw extruder, a kneader or a Banbury mixer, etc. can be used. have. In addition, the molding of the sheet using the resin composition is, for example, using a single screw extruder at a die temperature of 210 to 230 ° C, a cylinder temperature of 270 to 290 ° C, 230 to 250 ° C and 190 to 210 ° C, a screw speed of 80 to 95 rpm. It can be molded into a sheet with a thickness of about 1.0 to 1.5 mm under conditions.

Hereinafter, specific examples, comparative examples and experimental examples according to the present invention will be described.

First, the physical properties of the components used in Examples and Comparative Examples of the present invention are as follows.

(1) Linear Low Density Polyethylene (LLDPE)

LLDPE with a melt index (190° C., 2.16 kg load) of 1.1 g/10 min and a density of 0.921 g/cc was used.

(2) Low Density Polyethylene (LDPE)

LDPE having a melt index (190° C., 2.16 kg load) of 1 g/10 min and a density of 0.917 g/cc was used.

(3) Ethylene Vinyl Acetate (EVA)

EVA having a melt index (190° C., 2.16 kg load) of 4 g/10 min and a VA content of 26% by weight was used.

(4) Ultra-Low Density Polyethylene 1 (VLDPE1)

VLDPE having a melt index (190° C., load 2.16 kg) of 5 g/10 min, a density of 0.9 g/cc and a weight average molecular weight of 85,000 was used.

(5) Ultra-Low Density Polyethylene 2 (VLDPE2)

VLDPE having a melt index (190° C., load 2.16 kg) of 8 g/10 min, a density of 0.9 g/cc and a weight average molecular weight of 45,000 was used.

(6) ethylene octene copolymer (EOR)

An EOR having a melt index (190° C., load 2.16 kg) of 5 g/10 min (190° C., 2.16 kg), a density of 0.87 g/cc and a weight average molecular weight of 200,000 was used.

Example 1

40% by weight of linear low-density polyethylene, 40% by weight of ethylene vinyl acetate, and 20% by weight of ultra-low-density polyethylene 1 were mixed in a mixer, and then using a single screw extruder at a die temperature of 220°C, a cylinder temperature of 280, 240 and 200°C, respectively, and a screw speed of 85 About 1.1~1 at the condition of ~90 rpm. A sheet having a thickness of 3 mm was molded, and a specimen was taken in the TD direction with respect to the molded sheet.

Examples 2 to 3, Comparative Examples 1 to 6

Specimens were collected after sheet molding in the same manner as in Example 1, except that the components (1) to (6) in Example 1 were adjusted to the contents of Table 1 below.

test example

The physical properties of the sheets and specimens prepared according to the Examples and Comparative Examples were measured by the following method, and the results are shown in Table 1 below.

[How to measure]

1) Melt flow index

According to ASTM D 1238, it was measured under a load of 2.16 kg at 190°C.

2) Tensile strength and elongation

It was measured according to ASTM D 638, and a Type 1 specimen and a speed of 50 mm/min were used.

3) Ratio of components with a melting point of 95℃ or less

Using a differential scanning calorimeter, the ratio of the component having a melting point of 95°C or less was measured.

4) Adhesion test

The sheets were adhered at 170° C. and 50 bar conditions for 1 minute, and air at 600° C. and 2 bar was blown between the two sheets to determine pass or fail based on whether the adhesiveness was maintained.

Referring to Table 1, according to the present invention, when a resin composition for a waterproof sheet is prepared by combining a thermoplastic resin having a specific range of density, low density polyethylene, and ethylene vinyl acetate in a specific composition (Examples 1 to 3), tensile strength And it can be confirmed that the elongation is excellent and the adhesiveness is excellent.

On the other hand, it can be seen that when the thermoplastic resin having a density of 0.9 g/cc or less is not included (Comparative Example 2), elongation and adhesive properties are lowered. However, even if the thermoplastic resin is not included, when the EVA content is high (Comparative Example 1) ) The adhesive properties are excellent, but the elongation is somewhat lowered, and in this case, there is a problem in the waterproof properties.

On the other hand, when the content of the low-density thermoplastic resin is relatively small (Example 4), the elongation and adhesive properties are lowered, and when EOR is applied as a thermoplastic resin (Example 5) and ultra-low-density polyethylene having a relatively low molecular weight When applied (Example 6), it was found that the tensile strength was slightly lowered, and in particular, when the EVA content did not reach a certain level (Example 7), most of the physical properties including tensile strength, elongation and adhesive properties were somewhat lowered. From being, the physical properties and content ratios of the components employed in the present invention are very important factors in order to have very suitable properties for large waterproof sheets by implementing excellent adhesive properties and waterproof properties along with excellent tensile strength and elongation properties desired in the present invention. It can be confirmed that

A preferred embodiment of the present invention has been described in detail above. The description of the present invention is for illustration, and those of ordinary skill in the art to which the present invention pertains will understand that other specific forms can be easily modified without changing the technical spirit or essential features of the present invention.

Therefore, the scope of the present invention is indicated by the claims to be described later rather than the above detailed description, and all changes or modifications derived from the meaning, scope, and equivalent concept of the claims are included in the scope of the present invention. should be interpreted

Claims (8)

A resin composition for a waterproof sheet comprising 5 to 30% by weight of a thermoplastic resin having a density of 0.9 g/cc or less, 30 to 60% by weight of low-density polyethylene, and 20 to 50% by weight of ethylene vinyl acetate,
The thermoplastic resin is ethylene-octene rubber (EOR) or ethylene-butene copolymer (EBR),
The resin composition has a tensile strength (ASTM D 638) of 15 MPa or more, an elongation (ASTM D 638) of 700% or more, and a resin composition for a waterproof sheet, characterized in that the adhesion is maintained in an adhesion test according to the following method :
[Adhesive test method]
The two sheets made of the resin composition were adhered at 170° C. and 50 bar conditions for 1 minute, and air at 600° C. and 2 bar was blown to check whether the adhesiveness was maintained. delete According to claim 1,
The thermoplastic resin is a resin composition for a waterproof sheet, characterized in that the weight average molecular weight is 80,000 or more. According to claim 1,
The low-density polyethylene is a resin composition for a waterproof sheet, characterized in that the linear low-density polyethylene or branched low-density polyethylene. delete According to claim 1,
The resin composition for a waterproof sheet, characterized in that in the resin composition for a waterproof sheet, a component having a melting point of 95°C or less is 5 to 40% by weight of the total resin composition for a waterproof sheet. delete A sheet made of the resin composition of any one of claims 1, 3, 4 and 6.