KR102306914B1 - Film for Waterproof Sheet - Google Patents

Abstract

The present invention relates to a film for a waterproof sheet comprising a waterproofing material containing adhesive asphalt and a film attached to one surface of the waterproofing material, wherein the film of the present invention is a material containing high-density polyethylene and has a density of 0.945 g/cm 3 A first layer and a second layer formed by unidirectional stretching of the above polyethylene resin; A bonding layer disposed between the first layer and the second layer to bond the first layer and the second layer is laminated, and the bonding layer contains 70% or more of linear low-density polyethylene having a C6 or C8 comonomer. .

Description

Film for Waterproof Sheet

The present invention relates to a film for waterproofing sheets, and more particularly, to a film of a waterproofing sheet composed of a film attached to the surface of a waterproofing material made of rubberized asphalt material to protect the waterproofing material.

A method of attaching a waterproofing material to the surface is widely used for waterproofing the surface of a structure.

The waterproof sheet is composed of a synthetic resin film attached to one surface of a waterproofing material made of rubberized asphalt, etc., and the waterproofing material is attached to the concrete surface constituting the structure without a separate treatment to function as a waterproofing sheet.

As one of the technologies related to such a waterproof sheet, there is an invention related to an "asphalt-based waterproof sheet" disclosed in Korean Patent Application Laid-Open No. 10-2017-0014127 (Document 1).

The waterproof sheet according to the invention of Document 1 is composed of a waterproof film layer, a waterproof adhesive layer adhered to the surface of a structure, and a release paper removed during operation. The waterproof film layer is made of polyethylene resin, and the waterproof adhesive layer is a mixture of asphalt and thermoplastic elastomer. Such a waterproof sheet can be constructed without a separate treatment because the waterproof adhesive layer adheres to the surface of the structure.

In such a waterproof sheet, as a technology related to a film that is attached to the surface of a waterproof adhesive layer, which is a waterproofing material, to protect the waterproofing material, "high-strength film/board laminate and manufacturing method thereof" disclosed in US Patent Publication No. 485360 (Document 2) "There is an invention about

Document 2 discloses a film made by Valeron, Italy, formed by laminating two high-density polyethylene films whose orientation by stretching during extrusion crosses each other, and the Valeron film is a film layer of a waterproof sheet disclosed in Document 2 can also be used as

Valeron's film is effectively used as a film for waterproofing sheets, but because it depends on imports and is expensive, a film having the performance to replace it is developed and used in Korea.

A film developed and used in Korea is a high-density polyethylene having a thickness of about 150 μm or more, which is stretched in one direction.

Valeron film has a thickness of about 120㎛ or less, uniform thickness and physical properties, and good flexibility, but the replacement domestic film has a thickness of 150㎛ or more to satisfy the physical properties required by the standard (KS F4934) and has unidirectional orientation. .

However, this film nominally satisfies the standard specifications and has a low price, but the thickness is thick and the film's flexibility is low, so workability in the field is reduced. There is a problem that it is not.

Republic of Korea Patent Publication No. 10-2017-0014127 (Document 1) US Patent Publication No. 485360 (Document 2)

An object of the present invention is to provide a film used in a waterproof sheet of a configuration that can be manufactured in a constant quality while having physical properties required by standard standards in consideration of the problems of the prior art described above.

Specifically, the present invention is to provide a film for a waterproof sheet that satisfies the physical properties required by standard standards while using a unidirectionally oriented film instead of a cross-oriented and laminated film.

As a method for solving the problem, the inventors of the present invention considered forming a film for a waterproof sheet by laminating a unidirectionally stretched high-density polyethylene film that can be manufactured relatively inexpensively.

Since the conventionally used film for waterproofing sheet has unstable thickness and physical properties, a high-density polyethylene film unidirectionally stretched as in the prior art is used, but a uniform thickness and relatively stable physical properties can be obtained by laminating a plurality of these films and high density A separate bonding layer is used in laminating polyethylene films to bond to each other, but the attention has been paid to the fact that the bonding layer can contribute to the improvement of the physical properties of the film for waterproof sheets.

In the test conducted by the inventor of the present invention, when unidirectionally stretched high-density polyethylene films are laminated to each other to form a waterproof sheet film, other physical properties as a waterproof sheet film required by the standard may be satisfied, but the unidirectional stretched film It came to the conclusion that sufficient tear strength and softness could not be obtained due to the use of

According to this conclusion, the present invention that can manufacture a film for a waterproof sheet using various materials as a bonding layer and obtain uniform physical properties while satisfying the physical properties required by standard specifications through testing and measurement thereof led to the creation of a film of

The film for a waterproof sheet of the present invention is composed of a waterproofing material containing adhesive asphalt and a film attached to one surface of the waterproofing material,

a first layer and a second layer formed by unidirectional stretching of a polyethylene resin having a density of 0.945 g/cm 3 or more as a material containing high-density polyethylene;

A bonding layer disposed between the first layer and the second layer to bond the first layer and the second layer

It is laminated and composed,

The bonding layer contains 70% or more of linear low-density polyethylene having a C6 or C8 comonomer.

The first layer is made of high-density polyethylene as a main material and low-density polyethylene may be contained, but a polyethylene resin is mixed to have sufficient tensile strength to have a density of 0.945 g/cm 3 or more, which is the density range of high-density polyethylene.

In addition, it goes without saying that the first layer, the second layer, and the bonding layer are not made of only polyethylene resin and may contain various additives or fillers as necessary.

The film for a waterproof sheet according to the present invention satisfies the tear strength, tensile strength, and elongation required by standard specifications, and can be manufactured to have a relatively uniform thickness. In addition, since the film for a waterproof sheet according to the present invention is configured by bonding a unidirectionally stretched film, it can be manufactured inexpensively without using an expensive bidirectionally stretched film.

As an additional feature of the present invention, the film for a waterproof sheet of the present invention,

The first layer and the second layer have a thickness of 20-50 μm, the bonding layer has a thickness of 10-50 μm, and the first layer, the second layer and the bonding layer are laminated or coated by laminating or co-extrusion. can be formed.

When the thickness of the first layer and the second layer is less than 20 μm, respectively, extrusion and stretching of the film is difficult, and the film for a waterproof sheet does not satisfy sufficient tensile strength and tear strength.

Further, as the bonding layer, a material containing 70% or more of linear low-density polyethylene having a C6 or C8 comonomer and mixed with another polyolefin resin such as high-density polyethylene or low-density polyethylene can be used. In this case, when the bonding layer is extruded to a thickness of 10 μm or more, the waterproof sheet film may have the tear strength required by the standard specification, and when it is formed to a thickness exceeding 50 μm, the cost increases due to the use of excessive materials. And since the thickness of the film for waterproof sheets may become non-uniform, it is preferable to limit it to 50 μm or less.

In the above-described additional configuration, the material constituting the bonding layer is preferably a mixture of 30% or less of low-density polyethylene with respect to the total weight of linear low-density polyethylene having 70% or more of C6 or C8 comonomer.

By mixing low-density polyethylene without using 100% of linear low-density polyethylene having a C6 or C8 comonomer as a material for forming the bonding layer, the cost of the material becomes low while the film for waterproofing sheet can have sufficient tear strength.

Hereinafter, as a specific content for carrying out the present invention, the configuration of the film for a waterproof sheet according to an embodiment of the present invention will be described, and test results for physical properties in comparison with the film for a waterproof sheet according to a comparative example will be described.

The film for a waterproof sheet according to Example 1 of the present invention provides a film having a thickness of 50 μm, which is stretched only in one direction in the transverse direction and made of a high-density polyethylene resin as a first layer and a second layer constituting the outer periphery, and the first layer A three-layer film was formed by applying and laminating a linear low-density polyethylene resin formed with a metallocene catalyst between the second layer and the second layer.

The linear low-density polyethylene resin formed with the metallocene catalyst is applied to a thickness of 20 μm to form a bonding layer.

As the high-density polyethylene resin constituting the first and second layers, those sold under the name of 'YUZEX 8700' by SK Innovation were used. 'YUZEX 8700' has a density of 0.954 g/cm3, a melt index of 0.07 g/10min, a softening point of 123°C, a tensile strength at yield of 220 kg/cm2, and an elongation at break of 490%.

On the other hand, in the embodiment of the present invention, the first layer and the second layer are formed using only the high-density polyethylene resin as the resin material, but even if the low-density polyethylene resin is mixed in the range where the density is 0.945 g/cm 3 or more, the high-density polyethylene can be Sufficient physical properties can be obtained as in the case of using only paper.

As a material of the bonding layer, linear low-density polyethylene sold under the name of 'KC570S' by 'Japan Polyethlene Corporation' (JPE Corporation) of Japan was used.

'KC570S' is a kind of so-called 'metallocene polyethylene' manufactured using a metallocene catalyst, has a density of 0.906 g/cm3, a melt index of 10.5 g/10min, a melting point of 102 °C, and an elongation at break. It is more than 500%.

In this embodiment, JPE's linear low-density polyethylene 'KC570S' was used as a material for the bonding layer, but the present invention is not limited thereto, and other linear low-density polyethylene containing C6 or C8 as a comonomer may be used.

As such a linear low-density polyethylene, the one sold by SK Innovation under the name 'LLDPE FN810' can be used as one containing C8 comonomer, and the one sold by Hanwha Chemical under the name 'M1810HA' is C6. It can be used as one containing a monomer.

In order to determine whether the film thus formed can be used for a waterproof sheet, physical properties required by the standard were measured.

In addition, as Comparative Example 1 with respect to Example 1, the film constituting the first layer and the second layer was the same as in Example 1, and as a material for forming the bonding layer, a low-density film marketed by Hanwha Chemical under the name of '950'. A film was formed by laminating using a polyethylene resin, and physical properties thereof were measured.

'950' has a density of 0.919 g/cm 3 , a melt index of 7.5 g/10 min, a melting point of 105° C., a tensile strength at yield of 90 kg/cm 2 or more, and an elongation at break of 450%.

In addition, as Comparative Example 2, a bidirectionally stretched high-density polyethylene (HDPE) film having a thickness of 120 μm named 'Valeron Strength film' manufactured and sold by Valeron, Italy was purchased, and the same physical properties as in Example 1 and Comparative Example 1 was measured.

Table 1 shows the measured physical properties.

Test Items direction unit Test Methods Example 1 Comparative Example 1 Comparative Example 2 thickness μm ASTM D374 120 120 120 tear strength transverse N KS F 4934 27.5 20.7 48.2 tensile strength at break transverse kg/cm2 ASTM D638 419 419 435 longitudinal 451 451 460 yield tensile strength transverse kg/cm2 ASTM D638 245 245 285 longitudinal 257 257 289 elongation transverse % ASTM D638 325 325 679 longitudinal 349 349 636

As the physical properties required for the film for waterproof sheets, the physical properties required by the Korean standard (KS F4934) are 100 ~ 130 ㎛ thick, and the tear strength is 25 N or more in both the transverse and longitudinal directions.

Although the physical properties of the film for waterproofing sheets according to Example 1 of the present invention are lower than those of the film of Valeron of Comparative Example 2, it is known that it can be used as a film for waterproofing sheets by satisfying the values required by the standard specifications. can

On the other hand, the film of Comparative Example 1 used the same high-density polyethylene film as the first layer and the second layer as compared to the film of Example 1, but the resin constituting the bonding layer is generally low-density polyethylene used for bonding of the extrusion laminating method. A resin was used, and the same values as in Example 1 were shown in tensile strength and elongation, but it can be seen that the tear strength in the transverse direction does not have the physical properties required by the standard specification.

In the process of developing a film to replace Valeron's film of Comparative Example 2, the inventor of the present invention laminates two unidirectionally stretched high density polyethylene films rather than using an expensive bidirectionally stretched high density polyethylene film to make a film for waterproof sheets. In the case of configuration, it was determined that physical properties that could be substituted for Valeron's film could be obtained, and a film of Comparative Example 1 was prepared.

However, the film of Comparative Example 1 satisfied the physical properties required by the standard specifications in tensile strength, elongation, and longitudinal tear strength, but did not satisfy the physical properties required by the standard specifications in transverse tear strength, so it can be used as a film for waterproof sheets. found out that there was no

According to these prototypes and measurement results, films of various configurations were prepared and tested by changing the materials of the resin and the bonding layer for the first layer and the second layer, and as a result, a film having the same configuration as in Example 1 was obtained.

A linear low-density polyethylene named 'KC570S' of JPE Corporation used as a material for forming the bonding layer in the film of Example 1 is manufactured using a metallocene catalyst, and a C6 comonomer (condensed chain, Comonopmer) is included in the molecular structure. It is low density polyethylene.

Based on these test results, as a linear low-density polyethylene resin in which a C6 or C8 comomer is included in the molecular structure, 'LLDPE FN810' of SK Innovation, which was mentioned above, was used as a material for the bonding layer. The film of Example 2 was prepared under the same conditions as in Example 1, and the physical properties of the film of Example 2 were measured in the same manner as the measurement results in Table 1.

The measurement results are shown in Table 2 below.

Test Items direction unit Test Methods Example 2 thickness μm ASTM D374 120 tear strength transverse N KS F 4934 27.8 tensile strength at break transverse kg/cm2 ASTM D638 420 longitudinal 460 yield tensile strength transverse kg/cm2 ASTM D638 243 longitudinal 261 elongation transverse % ASTM D638 331 longitudinal 358

In light of the above measurement results, polyethylene resin was used for both the resin constituting the bonding layer in Examples 1 and 2 and the resin constituting the bonding layer in Comparative Example 1, but in Examples 1 and 2 within the scope of the present invention, the bonding layer As a resin constituting the C6 or C8 comonomer was used.

Next, as examples falling within the scope of the present invention and comparative examples outside the scope of the present invention, as a resin forming a bonding layer in Comparative Example 1 to JPE's 'KC570S' resin used as a resin forming a bonding layer in Example 1 A film was formed by using a resin obtained by mixing Hanwha Chemical's '950' low-density polyethylene resin in various amounts as a material for the bonding layer, and the physical properties thereof were measured.

As a result of the measurement of the physical properties, it was found that there is substantially no change in tensile strength or elongation according to the mixing content of the resin, and only the tear strength in the transverse direction changes according to the mixing ratio as shown in Table 4 below.

KC570S content
(%) L950 content
(%) Transverse tear strength
(N) 50 50 19.0 60 40 19.6 65 35 19.9 68 32 20.3 69 31 20.8 70 30 25.1 72 28 25.3 73 27 25.3 74 26 25.6 75 25 26.2 76 24 26.6 77 23 26.6 80 20 26.8 90 10 27.1 100 27.5 27.5

According to the above measurement results, the lateral tear strength gradually increased up to 69% of JPE's 'KC570S' resin as the resin constituting the bonding layer, but the tear strength required by the standard was not met.

However, at 70% of the content, the lateral tearing strength increased sharply to meet the tearing strength required by the standard specification, and the result was obtained that gradually increased up to 100%,

Next, as examples falling within the scope of the present invention and comparative examples outside the scope of the present invention, Hanwha Chemical's '950' low-density polyethylene resin used as a resin forming the bonding layer in Comparative Example 1 to 'M1810HA' resin of Hanwha Chemical A film was formed by using a resin mixed in various amounts as a material for the bonding layer, and the physical properties thereof were measured.

'M1810HA' linear low-density polyethylene resin from Hanwha Total Co., Ltd. has a density of 0.920 g/cm3, a melt index of 1.0 g/10min, a melting point of 120°C, a tensile strength at break of 450 kg/cm2, and an elongation at break of 670%.

As a result of the measurement of the physical properties, it was found that there is substantially no change in tensile strength or elongation according to the mixing content of the resin, and only the tear strength in the transverse direction changes according to the mixing ratio as shown in Table 5 below.

resin content
(%) L950 content
(%) Transverse tear strength
(N) 50 50 18.1 60 40 18.6 65 35 19.0 68 32 19.2 69 31 19.4 70 30 25.3 72 28 25.3 73 27 25.4 74 26 25.4 75 25 25.6 76 24 25.7 77 23 26.2 80 20 26.4 90 10 26.5 100 27.5 26.8.

According to the above measurement results, the lateral tear strength gradually increased until the content of 'M1810HA' resin as the resin forming the bonding layer was 69%, but it did not meet the tear strength required by the standard specification. However, the content was 70% From then on, the lateral tearing strength increased rapidly, meeting the tearing strength required by the standard specification, and the result was obtained with a gentle increase up to 100%.

According to the test and measurement results described in Tables 4 and 5 above, when the content of the resin constituting the bonding layer of Example 1 and the resin constituting the bonding layer of Example 2 is 70% or more, the physical properties required by the standard specification It has been confirmed that this can be achieved.

According to the inventor's consideration of these test and measurement results, it was found that the resin constituting the bonding layer in the films for waterproofing sheets of Examples 1 and 2 contributed to an increase in the lateral tear strength of the entire film.

In particular, in order for the films of these examples to meet the lateral tear strength required by the standard specification, a resin containing 70% or more of a linear low-density polyethylene resin having a C6 or C8 comonomer should be used as a bonding layer material. could check

In these resins, the fluidity of the resin is improved by the C6 or C8 comonomer, so that the bonding between the first and second layers is good, and the C6 or C8 comonomer improves the intermolecular bonding to reduce the tear strength of the entire film. appears to be high.

On the other hand, in the above embodiments, a film made of high-density polyethylene resin is used to form the first layer and the second layer of the film for waterproofing sheets, and the resins constituting the bonding layer are bonded to form a film by laminating them, but the first The film for waterproofing sheet may be co-extruded by using the resins forming the layer and the second layer and the resin forming the bonding layer as materials.

In addition, the film formed by co-extrusion also obtained test results substantially the same as the test and measurement results disclosed in Tables 4 and 5.

As mentioned above, the embodiments of the present invention have been described, the present invention is not limited to these embodiments, and various modifications and additions of configurations are possible within the scope described in the claims.

Claims (4)

delete A film for waterproofing sheets comprising a waterproofing material containing adhesive asphalt and a film attached to one surface of the waterproofing material,
a first layer and a second layer formed by unidirectional stretching of a polyethylene resin having a density of 0.945 g/cm 3 or more as a material containing high-density polyethylene;
A bonding layer disposed between the first layer and the second layer to bond the first layer and the second layer
It is laminated and composed,
The bonding layer contains 70% or more of linear low-density polyethylene having a C6 or C8 comonomer,
The first layer and the second layer have a thickness of 20-50 μm, the bonding layer has a thickness of 10-50 μm, and the first layer, the second layer, and the bonding layer are laminated or formed by laminating. Film for waterproofing sheet. A film for waterproofing sheets comprising a waterproofing material containing adhesive asphalt and a film attached to one surface of the waterproofing material,
a first layer and a second layer formed by unidirectional stretching of a polyethylene resin having a density of 0.945 g/cm 3 or more as a material containing high-density polyethylene;
A bonding layer disposed between the first layer and the second layer to bond the first layer and the second layer
It is laminated and composed,
The bonding layer contains 70% or more of linear low-density polyethylene having a C6 or C8 comonomer,
The first layer and the second layer have a thickness of 20 to 50 μm, the bonding layer has a thickness of 10 to 50 μm, and the film for a waterproof sheet is formed by co-extruding the first layer, the second layer and the bonding layer. . 4. The method according to claim 2 or 3,
The material constituting the bonding layer is a linear low-density polyethylene having 70% or more of C6 or C8 comonomer with respect to the total weight of the polyethylene and 30% or less of low-density polyethylene is mixed, a film for a waterproof sheet.