JP7468979B2 - Thermoplastic resin waterproofing material - Google Patents

Description

The present invention relates to a waterproofing material used in waterproofing structures such as building roofs, roofs, and verandas.

Conventionally, waterproof sheets have been laid in waterproof structures such as the rooftops, roofs, and verandas of buildings, and thermoplastic resin waterproof sheets are generally used. Other components used in waterproof structures, such as corner fittings and overflow pipes, are partially made of thermoplastic resin waterproof materials to improve adhesion with the waterproof sheet. These thermoplastic resin waterproof materials may contain plasticizers to give them flexibility. When the plasticizer in the thermoplastic resin waterproof material migrates to the surface of the waterproof material over time, dirt can easily adhere to the surface of the waterproof material that has been exposed to the outdoors for a long period of time, which not only deteriorates the appearance, but also in the case of waterproof materials with heat-shielding properties, the adhesion of dirt can prevent the heat-shielding properties from being fully exhibited.

On the other hand, there are thermoplastic elastomer-based waterproof sheets that do not contain plasticizers. Patent Document 1 discloses a waterproof sheet made of a thermoplastic elastomer. Patent Document 2 discloses a waterproof sheet in which a resin layer such as an acrylic resin or a fluororesin is provided on the surface of a plasticizer-containing polyvinyl chloride resin sheet to prevent the plasticizer from floating out.

JP 2002-201295 A Japanese Patent Application Laid-Open No. 9-1745

This type of waterproof sheet is less susceptible to dirt than a waterproof sheet made of thermoplastic resin containing plasticizers, but the sheet has poor flexibility, making it difficult to follow corners and entrances when installing the waterproof sheet. In addition, regardless of whether plasticizers are used or not, after installation, rainwater containing dirt such as dust from the atmosphere may accumulate on the sheet surface and then evaporate, causing dirt to adhere to the sheet. In addition, in Patent Document 2, the front and back surfaces of the waterproof sheet are made of different thermoplastic resins, so when adjacent sheets are joined by heat fusion or solvent welding, the front and back surfaces of the waterproof sheet have different thermal fusion properties and solubility in solvents, making them difficult to join and difficult to install.

The present invention aims to solve these problems and provide a waterproofing material that prevents dirt from sticking due to outdoor exposure to puddles while maintaining flexibility and ease of application.

The outline of the measures taken by the present invention to achieve the above objective is to provide a thermoplastic resin waterproofing material with a stain-resistant layer containing a surfactant on the outermost surface.

Specifically, it is a thermoplastic resin waterproofing material having, at least on the outermost surface, a stain-resistant layer that contains 20 to 80 parts by weight of a plasticizer and 0.1 to 10 parts by weight of a surfactant per 100 parts by weight of thermoplastic resin.

Furthermore, the above thermoplastic resin waterproofing material is one in which the surfactant is a nonionic surfactant, and the above thermoplastic resin waterproofing material is one or more selected from glycerin fatty acid ester compounds, sorbitan fatty acid ester compounds, sucrose fatty acid ester compounds, amine compounds, amide compounds, and these compounds, which are oxyalkylene, polyoxyalkylene, compounds having a hydroxyl group, oxyalkylene, polyoxyalkylene, alkyl ether compounds having a hydroxyl group, and oxyalkylene, polyoxyalkylene, alkyl phenyl ether compounds having a hydroxyl group.

Furthermore, the above thermoplastic resin waterproof material has a contact angle between the surface of the stain-resistant layer and water of less than 100°.

According to the present invention, by disposing the above-mentioned stain-resistant layer on the outermost surface, it is possible to provide a waterproof material that is flexible and easy to apply, and prevents the adhesion of stains caused by puddles.

FIG. 1 is a cross-sectional view showing one embodiment of a multilayer waterproof sheet, which is a thermoplastic resin waterproof material of the present invention. FIG. 1 is a cross-sectional view showing one embodiment of a single-layer waterproof sheet, which is a thermoplastic resin waterproof material of the present invention. FIG. 1 is a front view showing one embodiment of a corner joint component, which is a thermoplastic resin waterproofing material of the present invention. FIG. 1 is a perspective view showing one embodiment of an overflow pipe in which a flange surface is made of the thermoplastic resin waterproofing material of the present invention. FIG. 1 is a cross-sectional view showing one embodiment of a thermoplastic resin waterproof material of the present invention in which waterproof sheets are joined together. FIG. 1 is a perspective view showing an embodiment in which a waterproof sheet is a thermoplastic resin waterproof material of the present invention and a corner joint component are joined together. FIG. 1 is a perspective view showing one embodiment in which a waterproof sheet and a corner joint are joined together, the corner joint being a thermoplastic resin waterproof material of the present invention.

The following describes an embodiment of the present invention in detail.

The thermoplastic resin waterproof material (4) of the present invention has a stain-resistant layer on at least its outermost surface. Figure 1 shows a waterproof sheet (4-1) consisting of a stain-resistant layer (1) and a resin layer (2).
The substrate (3) may be provided between the stain-resistant layer (1) and the resin layer (2) as shown in Fig. 1, or may be provided as the bottom layer. The substrate may be omitted by laminating only the stain-resistant layer (1) and the resin layer (2). The resin layer may be a single layer or multiple layers, and in the case of multiple layers, each layer may have a different composition. Alternatively, the substrate may be a stain-resistant layer (1) only, as in the waterproof sheet (4-2) in Fig. 2.

Other examples of thermoplastic resin waterproofing materials include corner fittings used at outside and inside corners, and the flange surfaces of overflow pipes attached to the walls of roofs and verandas. Figure 3 shows a fitting for outside corners (4-3). Figure 4 shows a resin overflow pipe (5) with a flange surface (4-4). Fittings and flange surfaces are generally joined to cover the waterproof sheet, with the outdoor side forming a dirt-resistant layer (1). Fittings and flange surfaces, like the waterproof sheet, may be single-layered or multi-layered.

The thermoplastic resin waterproofing material of the present invention is characterized in that a surfactant is added to at least the outermost surface thereof. This is intended to improve the dirt-prevention performance of the waterproofing material. Waterproofing materials, such as waterproof sheets, are mainly used outdoors on rooftops, and their surfaces become dirty due to the accumulation of dust carried by rain and wind. In particular, when rainwater accumulates in the form of droplets on the surface of a waterproofing sheet during rainfall, the atmospheric dust contained in the rainwater in the droplets evaporates, leaving only the dirt attached to the waterproofing sheet, resulting in a spotted pattern that deteriorates the appearance. In the present invention, the addition of a surfactant makes the surface of the waterproofing material hydrophilic, making it difficult for water droplets to form on the surface during rainfall, thereby preventing the attachment of spotted dirt.

The surfactants added to thermoplastic resins rise to the surface of the thermoplastic resin, making the surface hydrophilic. This phenomenon is generally called bleeding or blooming (hereinafter referred to as bleeding, etc.). If a large amount of surfactant is added, bleeding, etc. is more likely to occur, and if a large amount of surfactant rises to the surface, it may actually make it easier for dirt to adhere to the surface.

The surfactant is added at least to the stain-prevention layer (1). The surfactant only needs to be added to the stain-prevention layer (1), and may or may not be added to the resin layer (2) or other layers. By adding the surfactant to the resin layer (2) and other layers, the surfactant will migrate to the stain-prevention layer (1) over time, and the effect can be expected to be sustained.

As surfactants, ionic surfactants such as anionic surfactants, cationic surfactants, and amphoteric surfactants, as well as nonionic surfactants can be used.

The thermoplastic resin waterproofing material of the present invention is usually molded by adding various materials to the thermoplastic resin, heating and mixing, and melt-kneading. Among the above surfactants, nonionic surfactants that have little effect on other additives and have good heat resistance during the molding process of the thermoplastic resin waterproofing material of the present invention are preferred.
The nonionic surfactants include glycerin fatty acid ester compounds, sorbitan fatty acid ester compounds, sucrose fatty acid ester compounds, amine compounds, amide compounds, and these compounds with oxyalkylene, polyoxyalkylene, and hydroxyl groups, alkyl ether compounds with oxyalkylene, polyoxyalkylene, and hydroxyl groups, and alkyl phenyl ether compounds with oxyalkylene, polyoxyalkylene, and hydroxyl groups, and two or more of these nonionic surfactants may be used in combination.In particular, from the viewpoint of heat resistance during processing, glycerin fatty acid ester compounds and sorbitan fatty acid ester compounds are preferred, and from the viewpoint of bleeding, sorbitan fatty acid ester compounds are even more preferred.

The amount of surfactant added is preferably 0.1 to 10 parts by weight per 100 parts by weight of thermoplastic resin in terms of heat resistance during processing, antifouling properties, and bleeding properties, more preferably 0.5 to 7 parts by weight in terms of antifouling properties, and even more preferably 0.5 to 5 parts by weight in terms of heat resistance. If the amount is less than 0.1 part by weight, there is almost no antifouling effect, and if it is 10 parts by weight or more, the surfactant will easily bleed onto the surface of the stain-preventing layer (1), and the antifouling properties will actually decrease.

The thermoplastic resin for the stain-prevention layer and the resin layer of the thermoplastic resin waterproof material of the present invention includes polyvinyl chloride resin, acrylic resin, vinyl acetate, polylactic acid, polyurethane elastomer, polyvinylidene chloride, etc., and two or more of these resins may be used in combination.
Examples of polyvinyl chloride resins include polyvinyl chloride resins which are vinyl chloride homopolymers, and copolymers of vinyl chloride with vinyl acetate, ethylene, (meth)acrylic acid esters, vinylidene chloride, and the like.
Examples of the acrylic resin include polymethyl methacrylate resin (PMMA), copolymers of acrylic acid with styrene, urethane, silicone, polyester, and the like.

Considering that the thermoplastic resin waterproofing materials of the present invention, for example the ends of multiple waterproof sheets are overlapped and solvent welded or heat fused together, it is preferable that the stain prevention layer (1) and the resin layer (2) are made of the same resin from the viewpoint of fusion adhesion. In other words, it is preferable that the joint surfaces of the thermoplastic resin waterproofing material are made of the same resin, and this is true whether the thermoplastic resin waterproofing material is a single layer or multiple layers.

In particular, polyvinyl chloride resins are preferred, as they offer excellent moldability, flexibility, and workability.

In particular, in the case of polyvinyl chloride resins, the plasticizers contained in them to give them flexibility make them more susceptible to dirt adhesion, so adding a surfactant increases the dirt-repellent effect.

The plasticizers for the stain-resistant layer (1) and the resin layer (2) include phthalic acid plasticizers, adipic acid plasticizers, polyester plasticizers, trimellitic acid plasticizers, phosphate ester plasticizers, epoxy plasticizers, and cyclohexane plasticizers, and two or more of these plasticizers may be used in combination. Phthalic acid plasticizers, such as DOP, DINP, and DUP, are particularly preferred in terms of weather resistance, durability, plasticization efficiency, compatibility, and processability. Phthalic acid ester plasticizers include DOP, DINP, and DUP, and DINP is more preferred in terms of volatility and stain adhesion when exposed to outdoors.

From the standpoint of moldability and flexibility, the amount of plasticizer added is preferably 20 to 80 parts by weight, more preferably 30 to 70 parts by weight, per 100 parts by weight of thermoplastic resin. If the amount is less than 20 parts by weight, sufficient flexibility cannot be obtained, and if the amount is more than 80 parts by weight, the plasticizer will float to the surface of the waterproofing material, which is not preferable.

The stain-prevention layer (1) can also contain a heat-shielding pigment with a solar reflectance of 50% or more in the near-infrared region of 780 to 2500 nm. This allows light in the near-infrared region to be efficiently reflected, so that the rise in surface temperature of the rooftop waterproof sheet can be made lower than that of ordinary rooftop waterproof sheets. This reduces the progress of thermal deterioration of the rooftop waterproof sheet, and also has the effect of mitigating the rise in temperature inside the building.
Examples of the heat-shielding pigment include phthalocyanine-based, azo-based, condensed azo-based, anthraquinone-based, perinone-perylene-based, quinacridone-based, triphenylmethane-based, dioxazine-based, titanium oxide-based, iron oxide-based (red iron oxide, yellow iron oxide), fired spinel-type pigments, lead chromate-based, Prussian blue-based, chromium oxide-based, composite oxide-based, and condensed polycyclic pigments.

Furthermore, by blending a heat-shielding pigment with a solar reflectance of 50% or more in the near-infrared region of 780 to 2500 nm in the stain-prevention layer (1), not only can the above-mentioned effects be achieved, but the stain-prevention function can also help maintain the heat-shielding performance over time.

In addition to the resin, plasticizer, and surfactant, various additives can be blended into the stain-prevention layer (1) and the resin layer (2), such as fillers, stabilizers, flame retardants, lubricants, and processing aids. In addition, since the thermoplastic resin waterproof material (4) is mainly used outdoors, it is desirable that the stain-prevention layer and the resin layer be highly weather-resistant resin compositions to which ultraviolet absorbers, light stabilizers, antioxidants, etc. have been added.

The substrate (3) can be a woven or nonwoven fabric made of polyester fiber, glass fiber, aramid fiber, vinylon fiber, etc.

The stain-prevention layer (1) and the resin layer (2) can be formed by mixing the resin, plasticizer, surfactant, and other additives and then forming them into a sheet by a calendar method, extrusion method, or the like. If a substrate (3) is used, the stain-prevention layer (1) and the resin layer (2) can be formed into a sheet by a calendar method, lamination method, or the like and then laminated onto the substrate (3).

The total thickness of the thermoplastic resin waterproof material (4) of the present invention thus obtained is preferably about 1.0 to 3.3 mm. In addition, the thickness of the stain-resistant layer (1) is preferably about 0.3 to 3.0 mm from the standpoint of stain resistance.

Figure 5 shows an embodiment of the construction structure in which a waterproof sheet (4-1), which is a thermoplastic resin waterproof material (4) of the present invention, is laid on a waterproof base and the ends of adjacent waterproof sheets are overlapped and joined at a joint (6). The stain-resistant layer (1) of the waterproof sheet (4-1) and the resin layer (2) of the other waterproof sheet are fused together at the joint (6). The waterproof sheet in Figure 5 consists of a stain-resistant layer (1) and a resin layer (2), but the waterproof sheet may be a single layer, in which case the stain-resistant layers (1) are joined together.

Figures 6 and 7 show an embodiment in which a jointing device for an outside corner is joined to an outside corner portion where a waterproof sheet is applied to the flat surface and the rising wall, which are the waterproof base. In Figure 6, the waterproof sheet is the thermoplastic resin waterproof material (4) of the present invention, and the jointing device for an outside corner is a general thermoplastic resin waterproof material (7). In Figure 7, the jointing device for an outside corner is the thermoplastic resin waterproof material (4) of the present invention, and the waterproof sheet is a general thermoplastic resin waterproof material (7). In this way, the thermoplastic resin waterproof material (4) of the present invention may be used as a part of the waterproof structure. In particular, it is preferable that the waterproof sheet, which usually covers a wide area, especially in the flat surface, is the thermoplastic resin waterproof material (4) of the present invention. In addition, by using the thermoplastic resin waterproof material (4) of the present invention over the entire surface of the waterproof structure, the waterproof structure is less likely to get dirty overall, and the beauty of the structure can be maintained.

Next, the present invention will be further explained by giving specific examples, but the present invention is not limited to these examples. All formulations in the following tables are shown in parts by weight unless otherwise specified.

A resin layer (2) having a thickness of 1.0 mm was obtained by calendar molding using a mixture consisting of 100 parts by weight of polyvinyl chloride resin, 70 parts by weight of a phthalate ester plasticizer, 3 parts by weight of a stabilizer, 50 parts by weight of calcium carbonate, and 2 parts by weight of a pigment, and a glass fiber woven fabric was laminated on the resin layer (2).
Next, 5 parts of stabilizer, 10 parts of calcium carbonate, and 5 parts of pigment were added to the formulations shown in Tables 1 to 3, and a stain-preventing layer (1) with a thickness of 0.5 mm was obtained by calendar molding. The stain-preventing layer (1) was then laminated with the resin layer (2) in which the above-mentioned glass fiber woven fabric was laminated to obtain a rooftop waterproof sheet. The pigment was a color that would give the obtained rooftop waterproof sheet a Munsell value of about N8. The following surfactants a to e were used, respectively.
a: Sorbitan fatty acid ester surfactant (non-ionic)
b: Glycerin fatty acid ester surfactant (non-ionic)
c: Amine surfactant (non-ionic)
d: Amide surfactant (non-ionic)
e: Cationic surfactant Comparative Example 8 in Table 3 is a waterproof sheet in which an acrylic resin layer made of an acrylic resin (without added plasticizer) is laminated on a resin layer made of a polychlorinated resin composition.
The obtained thermoplastic resin waterproofing material was evaluated for bleeding, heat resistance, contact angle, staining, flexibility, and melt adhesion according to the methods described below. The results are shown in Tables 1 to 3. Note that the evaluation of bleeding, heat resistance, contact angle, and staining was all carried out on the surface of the stain-preventing layer.

<Bleeding property>
Test specimens measuring 100 mm×100 mm were placed in a thermo-hygrostat at 40° C. and 80% humidity, and then taken out one month later and visually inspected for the presence or absence of bleeding.
〇: None △: Slightly present ×: Present

<Heat resistance test>
Test pieces measuring 100 mm x 100 mm were placed in a 180°C oven, and then removed after 60 minutes. The YI values of four randomly selected points were measured using a color computer (SM-4, manufactured by Suga Test Instruments Co., Ltd.), and the average value of the four points was calculated. ΔYI was calculated using the following formula.
ΔYI = [average YI after input] - [average YI before input]
◎: Less than 3 ○: 3 or more and less than 5 △: 5 or more and less than 10 ×: 10 or more

<Contact angle test>
A drop of tap water was dropped onto a test specimen measuring 10 mm x 30 mm, and a contact angle meter (Jasco International, Model FTA125) was used to photograph the contact state between the test specimen and the water from the side 25 seconds after the drop. The water contact angle was analyzed from the obtained image using the perfect circle fitting method.
(Test temperature: 23°C, Drop amount: 0.01 ml)
◯: Less than 90° △: 90° or more and less than 100° ×: 100° or more

<Staining test>
A test specimen measuring 300 mm x 300 mm was attached to an outdoor exposure test bench with a gradient of approximately 1/60, and after a three-month exposure test, the hue CIE L*a*b* was measured at four randomly selected points using a color computer (manufactured by Suga Test Instruments Co., Ltd., model SM-4) and the average value was calculated. The hue of the test specimen before exposure was also measured in the same manner. The ΔE* values before and after exposure, as well as the presence or absence of mottling caused by rainwater, were confirmed. ΔE* was calculated using the following formula.
ΔE*={([L* before exposure]-[L* after exposure])^2+([a* before exposure]-[a* after exposure])^2+([b* before exposure]-[b* after exposure])^2}^(1/2)
(Evaluation criteria)
Regarding ΔE*: ○: Less than 5.5 △: 5.5 or more and less than 6.5 ×: 6.5 or more Presence or absence of mottled patterns ○: Not visible △: Slightly visible ×: Clearly visible

<Flexibility>
A test specimen measuring 100 mm x 150 mm was cured in an environment of 23°C for 24 hours, and then the ease of bending when bent by hand was confirmed.
(Evaluation criteria)
○: Can be easily bent △: Can be bent with some resistance ×: Cannot be bent

<Solvent Weldability>
Two test pieces measuring 150 mm x 150 mm were placed with the stain-resistant layer facing up, and their ends were overlapped by a width of 40 mm. A brush soaked in a solvent (THF) was inserted into this overlapping part, and immediately after applying the solvent to both sides, the overlapping part was pressed from above by hand to be bonded, and the pressing time until the pieces were bonded to a point where they could not be easily peeled off by hand was measured.
(Evaluation criteria)
○: Less than 5 seconds △: 5 seconds or more, less than 10 seconds ×: 10 seconds or more

The evaluation results are shown in Tables 1 and 2 for the examples and in Table 3 for the comparative examples.

From Tables 1 to 3, it can be seen that in the Examples in which 1 to 10 parts by weight of a surfactant was added to the stain-preventive layer (1), the contact angle was smaller, and the evaluations of ΔE* and the presence or absence of mottled patterns were higher, showing excellent stain resistance, compared with Comparative Examples 1 to 3 in which no surfactant was added and Comparative Examples 4 and 6 in which the amount added was as small as 0.05 parts by weight. Among them, the sorbitan fatty acid ester surfactants of Examples 1 to 10 and the glycerin fatty acid ester surfactants of Examples 11 to 13 were excellent in heat resistance, and further, the sorbitan fatty acid ester surfactants were excellent in bleeding properties.
In addition, Comparative Examples 5 and 7 in Table 3 show that when the amount of surfactant added is too large, bleeding to the surface increases and stain resistance decreases. Comparative Example 8 showed results inferior to the Examples in both stain resistance and solvent weldability. This shows that the thermoplastic resin waterproofing material of the present invention is superior in stain resistance and workability compared to conventional waterproofing materials.

Table 4 shows the results of evaluating the staining property and solar reflectance retention rate after outdoor exposure of rooftop waterproof sheets whose outermost surface has a solar reflectance of 50% or more in the near-infrared region of 780 to 2500 nm. Examples 21 to 24 and Comparative Example 8 are rooftop waterproof sheets obtained in the same manner as Examples 1 to 20 and Comparative Examples 1 to 7, except that 5 parts of a pigment having heat-shielding properties was added to the stain-prevention layer instead of the pigment. Comparative Example 10 in Table 4 is a heat-shielding type waterproof sheet in which an acrylic resin layer made of an acrylic resin (without added plasticizer) is laminated on a resin layer made of a polychlorinated resin composition.
The fouling resistance and solar reflectance retention rate of each rooftop waterproof sheet were evaluated. The fouling resistance was evaluated in the same manner as ΔE* in Tables 1 to 3, and the solar reflectance retention rate was evaluated according to the method shown below. Note that all evaluations were performed on the surface of the stain-resistant layer.

<Solar reflectance retention rate>
A test specimen measuring 300 mm x 300 mm was attached to an outdoor exposure test bench with a gradient of about 1/60, and after 3 and 6 months of exposure tests, it was measured in the wavelength range of 780 to 2500 nm using a spectrophotometer V-570 (manufactured by JASCO Corporation). The solar reflectance was in accordance with JIS K 5602 (780 to 2500 nm). The solar reflectance retention was calculated as follows.
Solar reflectance retention (%) = ((solar reflectance after exposure)/(solar reflectance before exposure)) * 100
(Evaluation criteria)
◯: Solar reflectance retention rate is 85% or more △: Solar reflectance retention rate is less than 85%, 80% or more ×: Solar reflectance retention rate is less than 80%

From Table 4, it can be seen that Examples 21 to 24, in which a surfactant was added, have better stain resistance than Comparative Example 9, and the solar reflectance retention rate is also higher in the Examples, and the heat shielding performance is maintained. In addition, for Comparative Example 10, the solar reflectance retention rate drops sharply after long-term exposure, which is thought to be due to the decrease in stain resistance over time.

The rooftop waterproofing material of the present invention has excellent stain resistance and workability, so it can be widely used as a waterproofing material for rooftops, roofs, verandas, and other structures.

1 Stain-preventing layer 2 Resin layer 3 Substrate 4 Thermoplastic resin waterproof material 4-1 Waterproof sheet (multi-layer)
4-2 Waterproof sheet (single layer)
4-3 Corner joint accessories 4-4 Flange surface 5 Overflow pipe 6 Joint 7 Thermoplastic resin waterproof material

Claims (4)

A waterproof material made of thermoplastic resin, characterized in that it has, at least on its outermost surface, a stain-preventing layer containing 20 to 80 parts by weight of a plasticizer and 0.1 to 10 parts by weight of a surfactant per 100 parts by weight of a thermoplastic resin, and the thermoplastic resin is one of polyvinyl chloride resin, acrylic resin, vinyl acetate, polylactic acid , and polyvinylidene chloride, or a combination of two or more of these resins. The thermoplastic resin waterproofing material according to claim 1, characterized in that the surfactant is a nonionic surfactant. The thermoplastic resin waterproofing material according to claim 2, wherein the nonionic surfactant is at least one selected from glycerin fatty acid ester compounds, sorbitan fatty acid ester compounds, sucrose fatty acid ester compounds, amine compounds, amide compounds, and compounds having oxyalkylene, polyoxyalkylene, or hydroxyl groups among these compounds, alkyl ether compounds having oxyalkylene, polyoxyalkylene, or hydroxyl groups, and alkyl phenyl ether compounds having oxyalkylene, polyoxyalkylene, or hydroxyl groups. The thermoplastic resin waterproofing material according to any one of claims 1 to 3, characterized in that the contact angle between the surface of the stain-resistant layer and water is less than 100°.