JP4630588B2 - Polyurethane foam sheet material - Google Patents

Description

  The present invention relates to a polyurethane foam sheet material used for seals and gaskets of automobiles, homes, office automation equipment, computer peripheral devices, etc. that require airtightness, waterproofness, heat insulation, sound absorption, shock absorption, etc. The present invention relates to a polyurethane foam sheet material in which a foam sheet is used as a base material, an ultraviolet curable release layer is formed on one side, and an adhesive layer is provided on the other side.

Conventionally, a foam sheet in which a pressure-sensitive adhesive layer is formed on one surface of a foam made of a thermoplastic resin and a silicone release layer is provided on the other surface is known (see, for example, Patent Document 1).
Also, a release agent layer formed of ultraviolet curable silicone is provided on one side of the polyolefin foam sheet, and an adhesive layer formed by applying an acrylic photopolymerizable composition on the other side and irradiating it with ultraviolet rays. There is also known an adhesive tape provided with (for example, see Patent Document 2).
It is also known that a heat-insulating waterproof material is provided with a release treatment on one side of the heat-insulating foam and a waterproof rubber adhesive layer on the other side, and the release-treated surface side is a skin layer (for example, patents) Reference 3).
Also known is a pressure-sensitive adhesive foam sheet in which an adhesive layer is formed on a thermoplastic film laminated on one side of a soft foam and a release layer is provided on the other side (for example, (See Patent Document 4).
Furthermore, an adhesive layer is provided on one side of a polyolefin-based closed cell foam sheet having an apparent density of 0.017 to 0.060 g / cm ³ , and a recess having an average depth of 0.1 to 2 mm is provided on the other side. A foam pressure-sensitive adhesive sheet in which a release layer is provided on the concave surface is also known (see, for example, Patent Document 5).

A foam adhesive sheet with a release agent layer formed on one side of such a foam sheet and an adhesive layer provided on the other side does not require the work of peeling off the release paper during application (use) In addition, there are excellent effects such as not requiring disposal of release paper.
JP-A-4-359980 (Claims 0005 and FIG. 1). JP-A-6-49418 (Claim 1, 0013). JP-A-10-131314 (Claims and FIG. 1). JP-A-6-340852 (Claim 1 and FIG. 1). JP-A-10-330702 (Claim 1 and FIG. 5).

However, conventional foam sheets have the following problems as sound-absorbing materials, shock-absorbing materials, and air-tight / water-proof materials used after compression.
For those using thermoplastic resin as foam sheet, heat resistance is inferior, sound absorbing materials and cushioning materials are thin and change in dimensions, and airtight materials and waterproofing materials have poor compressive residual strain, maintaining long-term performance There is a problem lacking in nature.
This invention makes it the 1st objective to provide the polyurethane foam sheet material which solved such a subject.

In addition, as a result of intensive studies to solve the above problems, the present inventors found that a polyurethane foam of a thermosetting resin is preferable for the above solution, and based on the polyurethane foam of a thermosetting resin, A foam polyurethane foam sheet material having an ultraviolet curable release layer on one side and an adhesive layer on the other side was completed.
However, simply applying an ultraviolet curable release agent to the polyurethane foam base material will cause the release agent to penetrate into the resin before the release agent is cured if the amount of the release agent applied is small. The release layer becomes insufficient and the adhesive layer is difficult to peel off. On the contrary, when the application amount of the release agent is increased, the release agent is uncured and a part of the release agent is transferred to the adhesive layer, so that the adhesive force is reduced. Further, a long curing time is required for thick coating and sufficient curing. In addition, the cured layer becomes thick and a part of the release agent penetrates into the resin, so that flexibility is impaired.
This invention solves such problems and improves the adhesion to the construction surface by forming a release layer that is a thin film with a release layer that has been applied and cured in a small amount with a release agent. The second object is to provide a polyurethane foam sheet material having a release layer that can be easily peeled even when the pressure-sensitive adhesive layer is bonded.

Furthermore, in the polyurethane foam sheet material in which an ultraviolet curable release layer is formed on one side of the polyurethane foam base material and an adhesive layer is provided on the other side, the adhesive layer surface is applied for waterproofing purposes. Even if the adhesiveness with the surface is high and satisfactory waterproofness can be exhibited, there is a problem that the waterproofness cannot be exhibited when the release layer in contact with the construction surface cannot maintain the adhesiveness and hydrophobicity.
This invention makes it the 3rd objective to provide the polyurethane foam sheet material which solved such a subject.

In order to solve the above-mentioned problems, the polyurethane foam sheet material of the present invention has a solvent-free UV curable release layer formed on one side of a substrate formed of polyurethane foam and an adhesive layer provided on the other side. A polyurethane foam sheet material, wherein the base material formed of the polyurethane foam has a contact angle with water of 75 ° or more and an air permeability at a thickness of 10 mm of 20 cc / cm ² / sec or less. The surface of the substrate on which the release layer is applied is formed in a self-skin layer.
When the polyurethane foam sheet material is a roll-shaped product, if the release layer is thick, wrinkles are generated when the roll is unwound in flexibility, and the release layer becomes hard, brittle and easily broken. Further, it takes an ultraviolet curing time, and the amount of the release agent applied increases, resulting in an increase in cost. Therefore, it is preferable to form the release layer thinly. If the base material easily penetrates, a large amount of the permeated release agent exists in the surface layer portion, and the surface layer portion becomes hard, and if it is applied thinly, it penetrates and the releasability becomes insufficient.
In this invention, since the contact angle of polyurethane foam with water is set to 75 °, the penetration of the release agent can be delayed when the release agent is applied, and it is thin and flexible by applying a small amount of the release agent. A release layer can be formed. In order to delay the penetration of the release agent and form a thin release layer, a contact angle with water of 75 ° or more is sufficient, but in consideration of waterproofness and airtightness, a contact angle with water of 80 ° or more is preferable. Further, 90 ° or more is particularly preferable. When the polyurethane foam has a contact angle with water of 90 ° or more, a high water-stopping property is exhibited, so that it is particularly preferable for a sealing material that requires waterproofness and airtightness.
Also, according to this polyurethane foam sheet material, no release paper (release paper) is provided, so no release paper is required, and no work is required to peel off the release paper when the polyurethane foam sheet material is applied. In addition, it does not require disposal of release paper.

The lower the air permeability of the polyurethane foam, the smaller the opening of the cell membrane, and the easier it is to form a thin, solvent-free UV-curable release layer with good flexibility and surface adhesion. When the air permeability exceeds 20 cc / cm ² / sec, the number of openings becomes too large, the applied release agent also penetrates quickly and increases, and the flatness of the release layer surface also decreases. In addition, it is difficult to form a thin film. Therefore, the air permeability at a thickness of 10 mm is preferably 20 cc / cm ² / sec or less.

Furthermore, in order to uniformly form a solvent-free UV-curable release layer, it is necessary that the application surface of the release material is flat and the applied release agent does not penetrate into the substrate formed of polyurethane foam. is necessary. For this purpose, it is preferable to apply a release agent to the self-skin surface to form a release layer. The self skin thickness is particularly preferably 20 μm or less. This makes it possible to form a thin mold release layer having uniformity, flexibility and surface adhesion .

Moreover, the polyurethane foam sheet material of the present invention is characterized in that a reinforcing sheet is laminated on the surface of the base material formed of the polyurethane foam on which the pressure-sensitive adhesive layer is formed.
Thereby, in addition to the above effects, unnecessary stretch of the polyurethane foam sheet material can be prevented, and workability is also improved.

In addition, the ultraviolet curable release layer of the polyurethane foam sheet material of the present invention has a thickness after curing of 2 to 20 μm, and a contact angle with water after curing of 90 ° or more. Features.
When the release layer is formed thick, it lowers the flexibility of the polyurethane foam, requires a curing time, causes insufficient curing, and further increases the cost. If it is 2 μm or less, there is a risk of insufficient release effect. Therefore, the thickness of the release layer is preferably in the range of 2 to 20 μm. As a result, the flexibility is maintained, the releasing effect is sufficient, the curing time is short, and the working efficiency is improved. In addition, since the release layer has a thickness of 2 to 20 μm, the flexibility and surface adhesion are good, and since the contact angle with water is 90 ° or more, the waterproof and airtightness at the release layer portion is also high. It will be a thing.

According to the polyurethane foam sheet material of the present invention, the following effects can be obtained.
(1) Since the base material of the polyurethane foam sheet material is made of polyurethane foam, it has good compressive residual strain, maintains good cushioning properties for a long period of time, and has high heat resistance. Maintains performance such as airtightness, heat insulation and buffering. In addition, since the base material formed from this polyurethane foam selectively has conditions such as a contact angle with water of 75 ° or more and an air permeability of 20 cc / cm ² / sec or less, it is waterproof, airtight, and heat insulating. And therefore retains these performances over a long period of time.
(2) The polyurethane foam sheet material of the present invention has a solvent-free ultraviolet-curing release layer, and the release layer has a thickness in the range of 2 to 20 μm. Therefore, since the release layer has good flexibility and surface adhesion, and the release layer has a contact angle with water of 90 ° or more, the release layer is also highly waterproof, hydrophobic, airtight, etc. With performance. Thereby, even if it is a polyurethane foam sheet material which has a mold release layer, a high waterproof and airtight effect is exhibited with the whole polyurethane foam sheet material.
(3) Since the release layer is formed on the self-skin surface of the base material formed of the polyurethane foam, a uniform, flexible, and thin film release layer with good surface adhesion can be formed. Thereby, waterproofness and airtightness are also improved.
(4) According to the polyurethane foam sheet material of the present invention, release paper (release paper) is unnecessary, and not only the work of peeling the release paper during the pasting operation is required, but also the disposal of the release paper is necessary. do not do.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a partially enlarged perspective view of a polyurethane foam sheet material showing an embodiment of the present invention, and FIG. 2 is a perspective view of a modification of the polyurethane foam sheet material showing an embodiment of the present invention. .
This polyurethane foam sheet material 1 is configured such that a solvent-free UV-curable release layer 4 is formed on one side of a base material 2 formed of polyurethane foam, and an adhesive layer 3 is provided on the other side. Yes. This embodiment is an example in which the base material 2 is formed in a sheet shape with a polyurethane foam, and the polyurethane foam sheet material 1 is wound so that the release layer 4 and the pressure-sensitive adhesive layer 3 are in contact with each other. The case where it is made into a roll shape is shown.
FIG. 2 shows a case where the punched polyurethane foam sheet material 1 is stacked with the release layer 4 and the pressure-sensitive adhesive layer 3 in contact with each other. In the case of FIG. 2, the release paper 6 is laid on the lowermost part and is stacked on the release paper 6. Thereby, it can prevent that the adhesive layer 3 adheres to a mounting surface.
According to this polyurethane foam sheet material 1, the release layer 4 serves as a conventional release paper. Therefore, if the release layer 4 and the pressure-sensitive adhesive layer 3 are in contact with each other, they are wound or stacked. Since the pressure-sensitive adhesive layer 3 does not stick and easily peels without damaging the surface, it can be easily rewound (pulled out) or peeled off during use. With such a configuration of the polyurethane foam sheet material 1, the conventional release paper (release paper) is not required, and not only the work of peeling the release paper during the pasting operation is unnecessary, but also the disposal of the release paper. Is no longer needed.

The base material 2 formed of the polyurethane foam is formed of a polyurethane foam having a contact angle with water of 75 ° or more. When the contact angle of the polyurethane foam with water is 75 ° or more, the permeation of the release agent can be delayed when the release agent is applied, and a thin and flexible release layer can be formed by applying a small amount of the release agent. It can be formed uniformly. When the polyurethane foam sheet material is made into a roll-shaped product, if the release layer is thick, wrinkles are generated when the roll is unwound in flexibility, and the release layer becomes hard, brittle and easily broken. Further, it takes an ultraviolet curing time, and the amount of the release agent applied increases, resulting in an increase in cost. Therefore, it is preferable to form the release layer thinly.
When the contact angle with water is less than 75 °, penetration of the release agent into the substrate 2 starts immediately after application of the release agent, and a uniform film cannot be obtained. If the base material 2 is easy to permeate, a large amount of the permeated release agent will be present in the surface layer part, and the surface layer part will be hard, and if it is applied thinly, it will penetrate and the releasability will be insufficient. .
In order to delay the penetration of the release agent and form a thin release layer, a contact angle with water of 75 ° or more is sufficient, but in consideration of waterproofness and airtightness, a contact angle with water of 80 ° or more is preferable. Further, 90 ° or more is particularly preferable. When the polyurethane foam has a contact angle with water of 90 ° or more, a high water-stopping property is exhibited, so that it is particularly preferable for a sealing material that requires waterproofness and airtightness.

Further, the substrate 2 is formed by the polyurethane foam, formed by water and the contact angle 75 ° or more, an apparent density of 30kg / ^{m 3} or more, preferably polyurethane foam 30kg ^{/ m 3} ~200kg ^/ m 3 More preferably. If the apparent density of the substrate 2 formed of polyurethane foam is less than 30 kg / m ³ , the opening of the cell membrane increases, the cell diameter increases, and the formation of the release layer 4 becomes unstable, which is not preferable. A higher apparent density is preferable because the cell diameter is smaller and a release layer is easily formed.
There are also members whose apparent density of the base material 2 formed of polyurethane foam exceeds 200 kg / m ³ . Therefore, the apparent density may exceed 200 kg / m ³ . However, when the polyurethane foam base material 2 exceeds 200 kg / m ³ and the polyurethane foam base material 2 is usually too hard and requires waterproofness, airtightness, and heat insulation, there is a problem in terms of performance and construction. In addition, since the material cost is also expensive, 30 to 200 kg / m ³ is a preferable range. As a result, a polyurethane foam sheet material having good waterproofness, airtightness and heat insulation properties and excellent workability is obtained.

Further, the polyurethane foam forming the substrate 2 is preferably less 20 cc ^/ cm 2 / sec is air permeability in the thickness 10 mm, preferably particularly preferably less 10cc ^/ cm 2 ^/ sec.
This is because a polyurethane foam having a lower air permeability has fewer cell membrane openings, and it is easier to form a thin release layer 4 that is uniform, flexible, and has good surface adhesion. When the air permeability of the polyurethane foam 10 mm exceeds 20 cc / cm ² / sec, the cell membrane has too many openings, and the applied release agent also penetrates quickly, so the flexibility is impaired after curing. Since the amount of the release agent applied increases, it leads to an increase in cost, which is not preferable. In addition, the flatness of the surface of the release layer 4 also decreases, and it becomes difficult to form a thin film of the release layer 4, resulting in a decrease in flexibility and surface adhesion, leading to a decrease in waterproof and airtight performance.

Moreover, it is preferable that the surface which forms the release layer 4 of the base material 2 formed of the polyurethane foam is a self-skin surface. The release layer 4 is preferable because a uniform thin film has flexibility and surface adhesion, and waterproofness and airtightness are improved. In order to form the release layer 4 uniformly in a thin film, it is necessary that the application surface of the release agent is flat and the applied release agent does not penetrate from the application surface of the substrate 2 formed of polyurethane foam. is there. For this purpose, a self-skin surface is preferred. As a result, a thin release layer 4 having a uniform flexibility and surface adhesion can be formed.
In particular, the surface on which the release layer of the substrate 2 formed of polyurethane foam is formed is more preferably a self-skin surface with an opening ratio of 50% or less. When the self-skin surface has an opening ratio of 50% or less, the coated surface of the release material is flat, the applied release agent does not penetrate, and the release layer 4 is formed as a thin film having more uniformity, flexibility, and surface adhesion. it can.
The opening ratio of the self-skin is adjusted depending on the type and amount of the catalyst and auxiliary agent, the type of polyol and isocyanate, etc., in order to adjust the resinification.
In the present invention, the surface on which the release layer 4 of the substrate 2 formed of polyurethane foam is formed is preferably a self-skin surface .

The release layer 4 is formed by applying an ultraviolet curable release agent on one side of the substrate 2 formed of polyurethane foam and curing it by irradiation with ultraviolet rays. The ultraviolet curable mold release agent can be easily applied by a coating machine such as a gravure roll coater. The viscosity of the release agent is preferably 5,000 to 10,000 cp / 25 °. When the viscosity of the release agent is 5,000 to 10,000 cps / 25 °, it can be easily applied with a coating machine such as a gravure roll coater, and further, the penetration into the base material 2 is difficult to penetrate as the viscosity increases. .
Examples of the ultraviolet curable release agent include a solvent-free and cationic polymerizable silicone-based curing agent. Cationic polymerizable curing agents are preferred because they do not require management such as oxygen removal in an atmosphere that is cured by ultraviolet irradiation. The radical polymerizable curing agent cures in an oxygen-free atmosphere or in a state where oxygen is blocked in a film or the like.
When the release layer 4 is formed thick, it lowers the flexibility of the polyurethane foam and requires a curing time or insufficient curing, further increasing the cost. If it is 2 μm or less, there is a risk of insufficient release effect. Therefore, the thickness of the release layer 4 is preferably in the range of 2 to 20 μm. As a result, the flexibility is maintained, the releasing effect is sufficient, the curing time is short, and the working efficiency is improved.
Further, the release layer 4 preferably has a contact angle of 90 ° or more with water. If the contact angle with water is less than 90 °, the reliability of waterproofness and airtightness at the part of the release layer 4 is lowered when construction is performed. When the thickness of the release layer 4 is 2 to 20 μm, the flexibility and surface adhesion are good, and when the contact angle with water is 90 ° or more, the waterproof property and the air tightness at the release layer 4 portion are high. Become.

  Examples of the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer 3 include an acrylic pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive, and a hot-melt pressure-sensitive adhesive, and examples thereof include a solvent type or a water emulsion type. In order to improve the waterproof property of the polyurethane foam sheet material 1, a solvent type is preferable. When the polyurethane foam sheet material 1 is used as a waterproof material, it is preferable to use a solvent type. Among them, since the release agent is an ultraviolet curable type, an ultraviolet curable pressure-sensitive adhesive is more preferable in consideration of the production process.

FIG. 3 is a partially enlarged perspective view of a polyurethane foam sheet material showing another embodiment of the present invention. In this embodiment, a reinforcing sheet 5 is laminated on the surface of the substrate 2 formed of polyurethane foam on which the adhesive layer 3 is formed, and the adhesive layer 3 is formed on the surface of the reinforcing sheet 5. Since the others are the same as in the above embodiment, the same components are denoted by the same reference numerals, and detailed description thereof is omitted. According to this embodiment, since the reinforcing sheet 5 is provided, unnecessary elongation (elongation) of the polyurethane foam sheet material 1 can be prevented, the pasting work is facilitated, and the workability is improved.
Examples of the reinforcing sheet 5 include a thermoplastic film and a non-woven fabric, and examples of the thermoplastic film include a PET film. The reinforcing sheet 5 is preferably integrally formed with the base material 2 formed of polyurethane foam, but may be adhered to the base material 2 with an adhesive.
Next, examples and comparative examples of the present invention will be described. In this embodiment, a foam sheet in which an ultraviolet curable release layer 4 is formed on one side of a base material 2 formed of a polyurethane foam as shown in FIG. 1 and an adhesive layer 3 is provided on the other side. However, the substrate 2 and the release layer 4 are changed. In the following, a base material formed of polyurethane foam is simply referred to as a base material, and the apparent density is simply referred to as density.

The substrate has a density of 30 kg / m ³ , an air permeability of 3 cc / cm ² / sec, a contact angle with water of 95 °, and the surface on which the release agent is formed is the cell surface. A foam sheet in which a release agent is applied at 15 g / m ² on the cell surface on one side of the substrate, a release layer having a thickness of 11 μm is formed, and an adhesive layer is formed on the other side.

The substrate has a density of 30 kg / m ³ , an air permeability of 3 cc / cm ² / sec, a contact angle with water of 95 °, and the surface on which the release layer is formed is a self-skin surface with an aperture ratio of 20%. Yes. A foam in which a release agent is applied at 15 g / m ² on the self-skin surface of the base material having an opening ratio of 20%, a uniform release layer having a thickness of 14 μm is formed, and an adhesive layer is formed on the other surface. Sheet.

The substrate has a density of 30 kg / m ³ , an air permeability of 4 cc / cm ² / sec, a contact angle with water of 95 °, and the surface on which the release layer is formed is a self-skin surface with an open area ratio of 45%. ing. A foam in which a release agent is applied at 15 g / m ² on the self-skin surface of the base material having an opening ratio of 45%, a uniform release layer having a thickness of 13 μm is formed, and an adhesive layer is formed on the other surface. Sheet.

The base material has a density of 85 kg / m ³ , an air permeability of 0.5 cc / cm ² / sec, a contact angle with water of 97 °, and the surface on which the release layer is formed is a self-skin surface with an aperture ratio of 10% It has become. A foam sheet in which a release agent is applied at 15 g / m ^{2 on} the self-skin surface of the substrate, a uniform release layer having a thickness of 14 μm is formed, and an adhesive layer is formed on the other surface.

The substrate has a density of 200 kg / m ³ , an air permeability of 0.1 cc / cm ² / sec, a contact angle with water of 98 °, and the surface on which the release layer is formed is a self-skin surface with an aperture ratio of 2% It has become. A foam sheet in which a release agent is applied at 15 g / m ^{2 on} the self-skin surface of the substrate, a uniform release layer having a thickness of 14 μm is formed, and an adhesive layer is formed on the other surface.

The substrate has a density of 200 kg / m ³ , an air permeability of 0.1 cc / cm ² / sec, a contact angle with water of 98 °, and the surface on which the release layer is formed is a self-skin surface with an aperture ratio of 2% It has become. A foam sheet in which 5 g / m ^{2 of a} release agent is applied to the self-skin surface of this substrate, a uniform release layer having a thickness of 4 μm is formed, and an adhesive layer is formed on the other surface.

The substrate has a density of 35 kg / m ³ , an air permeability of 12 cc / cm ² / sec, a contact angle with water of 80 °, and the surface on which the release agent is formed is the cell surface. A foam sheet in which a release agent is applied at 15 g / m ² on the cell surface on one side of the substrate, a release layer having a thickness of 9 μm is formed, and an adhesive layer is formed on the other side.

Comparative Example 1

The base material has a density of 30 kg / m ³ , an air permeability of 3 cc / cm ² / sec, a contact angle with water of 95 ° (same as in Example 1), no release layer is provided, and it adheres to one side A foam sheet provided with an agent layer.

Comparative Example 2

The substrate has a density of 35 kg / m ³ , an air permeability of 15 cc / cm ² / sec, and a contact angle with water of 72 °, and a release agent is applied to the cell surface of this substrate at a thickness of 15 g / m ^2. A foam sheet in which a release layer of 6 μm is formed and an adhesive layer is formed on the other surface.

The ultraviolet curable release layers in Examples 1 to 6 and Comparative Example 2 were formed by coating with the following ultraviolet irradiation device using the following release agent.
UV-curable mold release agent UV-curable epoxy-based cationic silicone (no solvent) manufactured by Shin-Etsu Chemical Co., Ltd.
Main agent: X62-7622 (100 parts)
Curing agent: CAT7605 (1 part)
UV irradiation device Application roll Gravure roll use
Coating amount: 15 g / m ² (partially 5 g / m ² : Example 6)
Curing conditions Lamp: 60 w / cm
UV irradiation amount: 20 mJ / cm ²

  The results of conducting the effect tests such as coating tool combination (thickness, uniformity) of the release agent of the foam sheet in Examples 1 to 6 and Comparative Examples 1 and 2, the peelability from the pressure-sensitive adhesive layer, and the waterproof property are as follows. Table 1 shows the results.

○は良い、△はやや良い、×は悪いを示す。

○ indicates good, Δ indicates slightly good, and × indicates bad.

The values of the above test items are measured as follows.
(1) Density Physical property test of flexible polyurethane foam: Conforms to JIS K 6400.
(2) Air permeability Physical property test of flexible polyurethane foam: According to JIS K 6400.
The air permeability is measured at 5 mm of the foam sheet, and the 10 mm equivalent value is defined as the air permeability.
When the thickness of the foam measured for air permeability is around 5 mm, the measured thickness is converted.
In the case of having a self-skin, the measurement is performed in the same manner as described above.
(3) Contact angle with water A foam sheet having a thickness of 5 mm was sandwiched between aluminum foils, pressed at a temperature of 180 to 200 ° C. and a pressure of 40 to 50 kg / cm ² , and measured on a film with a contact angle meter. Value. As the contact angle meter, a Kyowa contact angle meter (manufactured by CA-A Kyowa Scientific Co., Ltd.) was used.
(4) Self-skin aperture ratio The surface aperture ratio of the self-skin is obtained by taking a photograph with a scanning electron microscope and calculating the ratio of the aperture area to the measurement area.
(5) Self-skin layer thickness For the self-skin thickness measurement, the foam sheet 1 is cut in the length direction as shown in FIG. An enlarged photograph is taken, the thickness of the adjacent rib 8 and the rib 9 in contact with the center line 10 is measured, and the average thickness is obtained. FIG. 4 is a schematic diagram of a scanning electron micrograph showing the measuring method.
(6) Thickness of release layer A foam sheet having a release layer is cut in the length direction, and an enlarged photograph of five arbitrarily determined release layer cross-sections is taken to determine the average film thickness. The measuring machine uses a scanning electron microscope.
(7) Peelability of pressure-sensitive adhesive layer An acrylic double-sided pressure-sensitive adhesive tape (# 5782 manufactured by Sekisui Chemical Co., Ltd.) is attached to the release layer, and the peelability is evaluated after 24 hours. Those that were easily peeled were marked with ◯, and those with poor peelability were marked with ×.
(8) Waterproofness The evaluation sample uses an acrylic double-sided adhesive tape affixed on one side. As shown in FIG. 5, the U-shaped punched product 1a having a thickness of 10 mm and a width of 15 mm has two smooth surfaces. After compression setting between the acrylic resin plates 11 and 11 via a 5 mm spacer 12, water is gently poured into the U-shaped portion, and after 4 hours, the water pressure without water leakage is evaluated as water-stopping.

According to the test results shown in Table 1, the following can be understood.
(A) When a release layer is formed as shown in Example 1 from a foam sheet having no release layer (Comparative Example 1), the release property of the adhesive layer is good. Furthermore, waterproofness improves.
(B) As for the surface on which the release layer is formed, the self-skin surface can form a uniform thin release layer as compared with the cell surface of Example 1 as shown in Examples 2 and 3, and the release layer The surface hardness is not increased and the surface maintains flexibility, the adhesion of the waterproof surface is improved, and the water-stopping property is improved.
(C) Compared to the density of 30 kg / m ³ shown in Examples 1 to 3, the 85 kg / m ³ of Example 4 and the 200 kg / m ³ of Examples 5 and 6 have higher airtightness and water stoppage and higher density. It is shown that the smaller the cell diameter, the better. In the case of a waterproof material, when it exceeds 200 kg / m ³ , the hardness increases, and problems such as an increase in construction cost and material cost arise. However, in applications that require high airtightness and high water-stopping properties, 200 kg / m ³ or more is also used.
(D) When the air permeability is low as in Examples 1 to 6, a release layer can be formed more uniformly than in the case of Comparative Example 2, and the water-stopping property is improved, and the pressure-sensitive adhesive for the release layer The peelability from the layer is also good.
(E) In the case of a contact angle of 72 ° with water shown in Comparative Example 2, the penetration of the release agent into the base material starts immediately after the release agent application, and a uniform film cannot be obtained. The peelability is poor and the water-stopping property (waterproofness) is also poor, and those having a higher contact angle with water as in Examples 1 to 6 can form a uniform and thin release layer, and also have water-stopping properties. It is high. In addition, when looking at the coating amount and film thickness of the release agent, the decrease in the film thickness with respect to the coating amount indicates that the penetration of the release agent into the base material is small, and each example This indicates that the characteristics are high. However, the substrate having a contact angle with water of 72 ° as in Comparative Example 2 has a film thickness of 6 μm even when the application amount of the release agent is 15 g / m ² as in Examples 1 to 5. It shows that there is much penetration of the release agent into the substrate.
Thus, according to the experimental results, it can be well understood that the polyurethane foam sheet material of the present invention has good characteristics.

  The above-described embodiments and examples do not limit the present invention, and various modifications are allowed without departing from the scope of the present invention.

It is a partially expanded perspective view of the polyurethane foam sheet material which shows embodiment of this invention. It is a perspective view which expands partially and shows the modification of the polyurethane foam sheet material which shows embodiment of this invention. It is a partially expanded perspective view of the polyurethane foam sheet material which shows another embodiment of this invention. It is a schematic diagram which measures the thickness of a self-skin layer. It is a schematic diagram of the measuring method which evaluates waterproofness.

DESCRIPTION OF SYMBOLS 1 Polyurethane foam sheet material 2 Base material formed with polyurethane foam 3 Adhesive layer 4 Release layer (solvent-free UV-curable release layer)
5 Reinforcing film 6 Release paper

Claims (3)

A polyurethane foam sheet material in which a solvent-free UV-curable release layer is formed on one side of a substrate formed of polyurethane foam, and an adhesive layer is provided on the other side, formed of the polyurethane foam The base material to be used has a contact angle with water of 75 ° or more and an air permeability at a thickness of 10 mm of 20 cc / cm ² / sec or less, and the surface of the base material on which the release layer is applied is self-skin A polyurethane foam sheet material characterized by being formed into a layer.   The polyurethane foam sheet material according to claim 1, wherein a reinforcing sheet is laminated on a surface of the base material formed of the polyurethane foam, on which the pressure-sensitive adhesive layer is formed. 3. The solvent-free UV curable release layer is formed to have a thickness of 2 to 20 [mu] m after curing, and a contact angle with water after curing is 90 [deg.] Or more. Polyurethane foam sheet material.

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