JP5431668B2 - Extensible adhesive sheet - Google Patents

Description

  The present invention relates to an extensible pressure-sensitive adhesive sheet that has good extensibility and adheres well to a portion having a curved surface or an uneven surface.

  As an adhesive tape for bonding a building member or the like, an adhesive tape using a butyl rubber-based or rubberized asphalt-based adhesive is known. Among such adhesive tapes, in order to improve the buffering property against the uneven surface, there is known one having a thick adhesive made of butyl rubber or the like.

  For example, in JP-A-10-58579 (Patent Document 1), an adhesive layer is laminated on one side of an extensible holding layer, and the elongation at break of the laminate is 100% or more and 100% stretched. It describes a stretchable sheet-like airtight material characterized in that the permanent set at the time is 20% or more. According to this stretchable sheet-like airtight material, it can be pasted while being arbitrarily and easily stretched in a shape corresponding to various deformed parts and curved parts during use, and the stretched part Since it is difficult to shrink, it is said that it has an advantage that peeling over time hardly occurs. However, although the sheet-like airtight material obtained using a butyl rubber-based or rubberized asphalt-based pressure-sensitive adhesive is said to be easy to use, there is a problem that the adhesive tends to sag at high temperatures and easily changes over time. When the thickness of the film is thick, the adhesion may be insufficient. In addition, black adhesives such as butyl rubber or rubberized asphalt may be attached to the hand during work, and dirt may be transferred to other building members. Furthermore, the sheet-like airtight material obtained using an acrylic pressure-sensitive adhesive is somewhat difficult to conform to a rough surface, and may not always be well along a curved surface or an uneven surface.

  JP 2001-3019 A (Patent Document 2) discloses a laminate in which a nonwoven fabric is laminated on at least one surface of a thermoplastic resin film, and the thermoplastic resin film and the nonwoven fabric are provided with an adhesive. The adhesive tape base material is characterized in that there is a film formed between two or more fibers in the fused portion of the fibers constituting the non-woven fabric. According to this adhesive tape substrate, the adhesive tape substrate is bonded to the thermoplastic resin film and the non-woven fabric without using an adhesive, so that the film and the non-woven fabric are peeled off even if the humidity or temperature environment changes. There is no. Moreover, since the film | membrane formed over two or more fibers exists in the melt | fusion part of the fiber which comprises a nonwoven fabric, it is said that hand-cut property is favorable. However, the pressure-sensitive adhesive tape prepared using such a base material for pressure-sensitive adhesive tapes with good hand cutting properties may cause the tape to break when it is extended.

Japanese Patent Laid-Open No. 10-58579 JP 2001-3019 A

  The present invention has been made to solve the above-described problems, and has an object to provide an extensible adhesive sheet that has excellent extensibility and that adheres well to a portion having a curved surface or an uneven surface. Is.

The above-mentioned problem is an extensible adhesive sheet in which a thermoplastic resin layer, a nonwoven fabric layer, and an adhesive layer are laminated, wherein the thermoplastic resin layer is a polyolefin having a layer thickness of 10 to 60 μm, and the nonwoven fabric layer is a thermoplastic elastomer. The basis weight of the non-woven fabric is 40 to 120 g / m ² , the basis weight of the pressure-sensitive adhesive layer is 15 to 300 g / m ² , and the resulting extensible adhesive sheet has a permanent strain of 20 to 80 after 100% elongation. %, And the elongation at break is 200% or more.

At this time, the thermoplastic resin layer is preferably made of polyolefin, and the pressure-sensitive adhesive layer is preferably made of an acrylic pressure-sensitive adhesive. The thickness of the thermoplastic resin layer is preferably 10 to 60 μm, the stress at 10% elongation is 5 N / cm or less, and the maximum point stress is preferably 10 N / cm or more. Furthermore, it is also preferable that the permanent set after extending 100% is 20 to 80%. By setting it as the extensible adhesive sheet provided with the thermoplastic resin layer of such conditions, while having the effect which reinforces a nonwoven fabric layer, the excessive expansion | extension and shrinkage | contraction of the nonwoven fabric layer after expansion | extension can be suppressed. A preferred embodiment of the present invention is a pressure-sensitive adhesive tape for joining building members comprising such an extensible pressure-sensitive adhesive sheet.

  The extensible pressure-sensitive adhesive sheet of the present invention has good extensibility and adheres well to a portion having a curved surface or an uneven surface. Therefore, it is suitable as a pressure-sensitive adhesive tape for joining building members, and is suitably used for the boundary portions of building members that require airtightness and watertightness.

  The extensible adhesive sheet of the present invention is a laminate of a thermoplastic resin layer, a nonwoven fabric layer, and an adhesive layer.

  The thermoplastic resin constituting the thermoplastic resin layer used in the present invention is not particularly limited, and polyolefin, polyester, polyamide, polyvinyl chloride, etc. can be used, but it has extensibility and good chemical resistance. Polyolefin is preferable from the viewpoint. Examples of polyolefins include low-density polyethylene, linear low-density polyethylene (including ethylene-α-olefin copolymers produced using a metallocene catalyst), high-density polyethylene, polypropylene, propylene-ethylene block copolymer, propylene. -Ethylene random copolymer, ethylene-vinyl acetate copolymer (EVA), ethylene-ethyl acrylate copolymer (EEA), ethylene-vinyl alcohol copolymer (EVOH), etc. From the viewpoint of maintaining good permanent distortion, low-density polyethylene and linear low-density polyethylene are preferably used.

  In the stretchable pressure-sensitive adhesive sheet of the present invention, the thickness of the thermoplastic resin layer is not particularly limited, but is preferably 10 to 60 μm from the viewpoint of suppressing excessive stretching and shrinkage of the nonwoven fabric layer. When the thickness of the thermoplastic resin layer is less than 10 μm, the tensile strength at break is insufficient, and it is not only easily broken by external stress, but also when the thermoplastic resin layer is laminated with a non-woven fabric layer, a hole is opened in the thermoplastic resin layer. The airtightness and watertightness of the extensible adhesive sheet may be impaired. The thickness of the thermoplastic resin layer is more preferably 15 μm or more, and further preferably 20 μm or more. On the other hand, when the thickness of the thermoplastic resin layer exceeds 60 μm, the force required to extend the thermoplastic resin layer becomes too large and becomes too hard. There is a risk that it will be difficult to follow. The thickness of the thermoplastic resin layer is more preferably 55 μm or less, and further preferably 50 μm or less.

  The nonwoven fabric constituting the nonwoven fabric layer used in the present invention is not particularly limited, and is formed by a nonwoven fabric formed by a spunbond method (spunbond nonwoven fabric), a nonwoven fabric formed by a meltblown method (meltblown nonwoven fabric), or a hydroentanglement method. Nonwoven fabric (spun lace nonwoven fabric), nonwoven fabric formed by needle punch method, nonwoven fabric formed by heat fusion method (thermal bond nonwoven fabric), nonwoven fabric formed by solvent bonding method (chemical bond nonwoven fabric), formed by card method Nonwoven fabrics that have been used. Among these, a spunbond nonwoven fabric, a spunlace nonwoven fabric, and a meltblown nonwoven fabric are preferably used from the viewpoint of good extensibility.

  The material for the nonwoven fabric is not particularly limited, but is preferably a nonwoven fabric made of a thermoplastic elastomer from the viewpoint of having a high elongation at break and being flexible and capable of being stretched with a smaller force. Examples of the thermoplastic elastomer include olefin elastomers, styrene elastomers, urethane elastomers, and nylon elastomers. If the adhesion between the nonwoven fabric layer and the thermoplastic resin layer is weak, delamination may occur and the airtightness and watertightness may be impaired, so the material of the nonwoven fabric layer should be a material with good adhesion to the thermoplastic resin layer. Selected. Therefore, when selecting polyolefin as a thermoplastic resin layer, an olefin-type elastomer or a styrene-type elastomer is used suitably for a nonwoven fabric layer.

In the extensible pressure-sensitive adhesive sheet of the present invention, the basis weight of the nonwoven fabric layer (representing the mass per unit area) is 40 to 120 g / m ² . When the basis weight of the nonwoven fabric layer is in such a range, an extensible pressure-sensitive adhesive sheet that has good extensibility and adheres well to a portion having a curved surface or an uneven surface can be obtained. When the basis weight of the nonwoven fabric is less than 40 g / m ² , the extensible adhesive sheet is inferior in adhesion and buffering properties to a portion having a curved surface or a concavo-convex surface, and when the convex surface is sharp, there is a possibility that a hole may be opened and torn. The basis weight of the nonwoven fabric is preferably 50 g / m ² or more, more preferably 60 g / m ² or more, and further preferably 70 g / m ² or more. On the other hand, when the basis weight of the nonwoven fabric exceeds 120 g / m ² , the strength required to stretch the nonwoven fabric becomes high, so that it becomes difficult to stretch, and the thermoplastic resin layer and the nonwoven fabric layer are delaminated during stretching. There is a fear. In particular, when the strength of the nonwoven fabric layer becomes higher than that of the thermoplastic resin layer in the process of stretching, the possibility of delamination increases. The basis weight of the nonwoven fabric layer is preferably 110 g / m ² or less, more preferably 100 g / m ² or less, and still more preferably 90 g / m ² or less.

  It does not specifically limit as an adhesive which comprises the adhesive layer used by this invention, An acrylic adhesive, a rubber adhesive, a silicone adhesive, etc. can be used. Among them, an acrylic pressure-sensitive adhesive that is excellent in heat resistance, weather resistance, and solvent resistance, is well-familiar with the object to be adhered, has little dirt due to the pressure-sensitive adhesive, and has good workability such as easy stacking is preferable.

In the extensible adhesive sheet of the present invention, the basis weight of the adhesive layer is 15 to 300 g / m ² . When the basis weight of the pressure-sensitive adhesive layer is in such a range, an extensible pressure-sensitive adhesive sheet having good adhesiveness and high airtightness and watertightness can be obtained. When the basis weight of the pressure-sensitive adhesive layer is less than 15 g / m ² , the adhesiveness is weak and the sheet may be peeled off, preferably 20 g / m ² or more, more preferably 30 g / m ² or more, More preferably, it is 40 g / m ² or more. On the other hand, when the basis weight of the pressure-sensitive adhesive layer exceeds 300 g / m ² , the pressure-sensitive adhesive may protrude from the end surface of the sheet. In particular, if the adhesive sticks out of the end face of the sheet when it is wound on a roll, dust will easily adhere to the end face of the roll, and when it is placed with the end face down, it will adhere to the floor and peel off. There is a high risk of damaging the floor. The basis weight of the pressure-sensitive adhesive layer is preferably 250 g / m ² or less, more preferably 200 g / m ² or less, and even more preferably 150 g / m ² or less.

  The extensible pressure-sensitive adhesive sheet of the present invention is a laminate of these thermoplastic resin layer, nonwoven fabric layer, and pressure-sensitive adhesive layer. When the extensible pressure-sensitive adhesive sheet of the present invention includes the thermoplastic resin layer, it has an effect of reinforcing the nonwoven fabric layer and can suppress excessive elongation and shrinkage of the nonwoven fabric layer after elongation. Moreover, while being able to improve the intensity | strength of an extensible adhesive sheet, waterproofness can also be provided. Furthermore, when the extensible pressure-sensitive adhesive sheet of the present invention is provided with a nonwoven fabric layer, adhesion and buffering properties with respect to a portion having a curved surface or an uneven surface are improved. At this time, it is preferable to reduce the thickness of the thermoplastic resin layer and to make the nonwoven fabric layer thicker than the thermoplastic resin layer because an extensible adhesive sheet having excellent adhesion to a curved surface or an uneven surface can be obtained. Although it does not specifically limit as a layer structure of a thermoplastic resin layer, a nonwoven fabric layer, and an adhesive layer, From a viewpoint that the adhesiveness with respect to a curved surface or an uneven surface is more favorable, a thermoplastic resin layer, a nonwoven fabric layer, and an adhesive layer are used. It is preferable to laminate in this order.

  The extensible pressure-sensitive adhesive sheet of the present invention is characterized in that the elongation at break is 200% or more. Here, the elongation at break is calculated from the difference between the initial length of the sample and the length after elongation of the sample when the sample is stretched at a constant speed by a tensile tester, in accordance with JIS Z 0237. Measured. When the elongation at break is 200% or more, it becomes an extensible pressure-sensitive adhesive sheet having good adhesion when bonded easily. The larger the elongation at break, the more along a curved surface with a smaller diameter or an uneven surface having a sharper angle. When the elongation at break is less than 200%, it does not fit along a curved surface or an uneven surface, and when the convex surface is sharp, there is a possibility that a hole will open and break. The elongation at break is preferably 300% or more, more preferably 400% or more, and further preferably 500% or more. On the other hand, the elongation at break is usually 2000% or less.

  Further, the stretchable pressure-sensitive adhesive sheet of the present invention preferably has a 10% elongation stress of 5 N / cm or less. Here, the stress at 10% elongation refers to the stress when the sample is elongated by 10% from the initial length of the sample by the tensile tester on the basis of the initial length of the sample, and conforms to JIS Z 0237. Measured. If the stress at 10% elongation exceeds 5 N / cm, the initial load is applied when using the sheet, which may make it difficult to stretch, and the sheet becomes hard and does not follow the curved or uneven surface. There is a fear. The stress at 10% elongation is more preferably 4 N / cm or less.

  Furthermore, the extensible adhesive sheet of the present invention preferably has a maximum point stress of 10 N / cm or more. Here, the maximum point stress means the maximum stress when stretched by a tensile tester, and is measured according to JIS Z 0237. When the maximum point stress is less than 10 N / cm, the sheet may be easily broken when the sheet is stretched, and the maximum point stress is more preferably 11 N / cm or more. On the other hand, the maximum point stress is usually 100 N / cm or less.

  Moreover, it is preferable that the permanent set after extending | stretching 100% is 20 to 80% after the extensible adhesive sheet of this invention. Here, the permanent strain after 100% elongation is the percentage of the degree of change that the sample shrinks after a certain time has elapsed after 100% elongation of the sample with a tensile tester. Is described in the method for measuring permanent set in the examples described later. If the permanent set after stretching 100% is less than 20%, the sheet has a strong force to return to the state before stretching, and the bonded sheet may be peeled off. The permanent set after 100% elongation is more preferably 25% or more, and further preferably 30% or more. On the other hand, if the permanent strain after 100% elongation exceeds 80%, the force of the sheet returning to the state before elongation is weak, and it may be difficult to adhere to a portion having a curved surface or an uneven surface. The permanent set after 100% elongation is more preferably 75% or less, and still more preferably 70% or less.

  The extensible pressure-sensitive adhesive sheet of the present invention has good extensibility and adheres well to a portion having a curved surface or an uneven surface. Therefore, it is suitably used as a pressure-sensitive adhesive tape for joining building members, and particularly suitable for a boundary portion between building members such as pipes in order to enhance airtightness or watertightness.

  Hereinafter, the present invention will be described more specifically with reference to examples. The measurement method and evaluation method in this example are as follows.

(1) Measurement of elongation at break A test piece of an extensible adhesive sheet having a width of 25 mm and a length of 100 mm was prepared. According to JIS Z 0237, this test piece was set in a tensile tester and extended at 23 ° C. at a speed of 300 mm / min until breaking. The elongation at this time was measured to obtain the elongation at break. The elongation at break (%) was calculated by [(length after elongation−initial length) / (initial length)] × 100.

(2) Measurement of stress at 10% elongation A test piece of an extensible adhesive sheet having a width of 25 mm and a length of 100 mm was prepared. According to JIS Z 0237, this test piece was set in a tensile tester, and the stress was measured when it was stretched 10% from the initial length of the test piece at a speed of 300 mm / min at 23 ° C. Was 10% elongation stress.

(3) Measurement of maximum point stress A test piece of an extensible adhesive sheet having a width of 25 mm and a length of 100 mm was prepared. According to JIS Z 0237, this test piece is set in a tensile tester, and the stress is measured when it is stretched until it breaks at 23 ° C. at a speed of 300 mm / min. Was the maximum point stress.

(4) Measurement of permanent distortion after 100% elongation A test piece of an extensible adhesive sheet having a width of 25 mm and a length of 100 mm was prepared. Lines were drawn with oil-based pens at two locations of 37.5 mm from both ends in the length direction (the distance between the lines was 25 mm). The test piece was set in a tensile tester set to 50 mm between chucks, extended 50 mm at a speed of 500 mm / min, and left in this state for 2 minutes. Thereafter, the test piece was taken out and left for 24 hours in a state where no tension was applied, and the distance between the lines was measured. Permanent strain (%) was calculated by [(distance between lines after test−25 mm) / (25 mm)] × 100.

(5) Adhesive evaluation A 30 cm high prism (wood) having a 10 cm side bottom was placed in the center of a 30 cm side square plate (wood), and the bottom was obtained. Adhesion was evaluated by pasting together the boundary part of a plate and a prism along the periphery of a prism using a tape formed by slitting an extensible adhesive sheet to a width of 50 mm.

Example 1
A linear low density polyethylene (density = 0.911 g / cm ³ ) was extrusion laminated to one side of a spunbonded nonwoven fabric having a basis weight of 100 g / m ^{2 made} of a polypropylene elastomer. This formed the sheet base material with which the 40-micrometer-thick thermoplastic resin layer and the nonwoven fabric layer were laminated | stacked. An acrylic pressure-sensitive adhesive was applied to the nonwoven fabric surface of the sheet substrate with a multi-coater so that the basis weight after drying was 100 g / m ² and dried to obtain an extensible pressure-sensitive adhesive sheet. The elongation at break of the obtained extensible pressure-sensitive adhesive sheet was measured for 10% elongation stress, maximum point stress, and permanent strain after 100% elongation. The obtained results are summarized in Table 1. Moreover, when the adhesiveness was evaluated, the adhesiveness was good, and it was possible to easily adhere to the corners of the columns and bond them together.

Comparative Example 1
A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 except that a spunbonded nonwoven fabric having a basis weight of 100 g / m ^{2 made} of polypropylene (non-elastomer) was used instead of the polypropylene-based elastomer. The results measured in the same manner as in Example 1 are summarized in Table 1. Moreover, when the obtained adhesive sheet was bonded around the square pillar, it was hard to elongate and could not be adhered well. Furthermore, wrinkles were generated when they were bonded together.

Comparative Example 2
In Example 1, the adhesive sheet was produced like Example 1 except having used the nonwoven fabric of 150 g / m < ² > of fabric weights. The results measured in the same manner as in Example 1 are summarized in Table 1. Moreover, when the obtained adhesive sheet was bonded around the square pillar, it was difficult to expand and required force when being bonded to the corner of the pillar. Furthermore, when it extended | stretched too much, delamination occurred between the thermoplastic resin layer and the nonwoven fabric layer.

Comparative Example 3
In Example 1, the adhesive sheet was produced like Example 1 except having used the nonwoven fabric of 30 g / m < ² > of fabric weights. When the sheet was produced, curling occurred violently and the paste coating property was not good. The results measured in the same manner as in Example 1 are summarized in Table 1. Moreover, when the obtained adhesive sheet was bonded around the square pillar, tearing occurred unless it was carefully stretched. Furthermore, it was not possible to make a close contact with a portion having a curved surface or an uneven surface.

Example 2
In Example 1, an extensible adhesive sheet was produced in the same manner as in Example 1 except that the thickness of the thermoplastic resin layer was changed to 80 μm. The results measured in the same manner as in Example 1 are summarized in Table 1. Moreover, when the obtained extensible pressure-sensitive adhesive sheet was bonded around a square column, a force was required for bonding to the corner portion of the column. Furthermore, wrinkles were generated when they were bonded together.

Example 3
In Example 1, instead of a spunbonded nonwoven fabric having a basis weight of 100 g / m ^{2 made} of a polypropylene-based elastomer, a spunlace nonwoven fabric having a basis weight of 70 g / m ^{2 made} of a styrene-based elastomer was used and stretched in the same manner as in Example 1. An adhesive sheet was prepared. The results measured in the same manner as in Example 1 are summarized in Table 1. Further, when the obtained extensible pressure-sensitive adhesive sheet was bonded to the periphery of a rectangular column, the adhesiveness was good, and it was possible to easily adhere and bond to the corner portion of the column.

Comparative Example 4
In Example 1, without providing the thermoplastic resin layer, instead of the spunbonded nonwoven fabric having a basis weight of 100 g / m ² of polypropylene-based elastomer, except for using the spun lace nonwoven fabric having a basis weight of 100 g / m ² consisting of styrene-based elastomer A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1. The results measured in the same manner as in Example 1 are summarized in Table 1. Moreover, when the obtained adhesive sheet was bonded around the square pillar, there was no particular problem, but it was confirmed that the end of the adhesive sheet was peeled off 3 days after bonding.

Comparative Example 5
A pressure-sensitive adhesive sheet was prepared by bonding a butyl rubber-based pressure-sensitive adhesive having a basis weight of 900 g / m ^{2 to} one side of a 30 μm-thick film made of low-density polyethylene (density = 0.918 g / cm ³ ). The results measured in the same manner as in Example 1 are summarized in Table 1. Moreover, when the obtained adhesive sheet was bonded around the square pillar, it was difficult to make it fit along the corner of the pillar.

As can be seen from Table 1, a linear low density polyethylene as the thermoplastic resin layer, a spunbond nonwoven fabric with a basis weight of 100 g / m ^{2 made} of a polypropylene elastomer as the nonwoven fabric layer, and an acrylic system with a basis weight of 100 g / m ² as the adhesive layer. In Example 1 using an adhesive, extensibility was good, and an extensible adhesive sheet was obtained that adhered well to a portion having a curved surface or an uneven surface. On the other hand, in Comparative Example 1 in which the elongation at break was 90%, it was difficult to elongate the pressure-sensitive adhesive sheet, and it was not possible to achieve good adhesion. In Comparative Example 2 in which the basis weight of the nonwoven fabric layer was 150 g / m ² , delamination occurred between the thermoplastic resin layer and the nonwoven fabric layer when the adhesive sheet was stretched too much. In Comparative Example 3 in which the basis weight of the nonwoven fabric layer was 30 g / m ² , the non-woven fabric layer could not be well adhered to a portion having a curved surface or an uneven surface, and the maximum point stress was 9 N / cm, which was a little low in strength. . Furthermore, in Comparative Example 4 in which the thermoplastic resin layer was not provided, the permanent strain after 100% elongation was 15%, and the pressure-sensitive adhesive sheet had a strong force to return to the state before elongation. Later, the edge of the adhesive sheet was peeled off. Moreover, in the comparative example 5 which did not provide a nonwoven fabric layer, it was difficult to make it follow along the site | part which has a curved surface and an uneven surface, especially the corner | angular part of a pillar.

Claims (4)

An extensible adhesive sheet in which a thermoplastic resin layer, a nonwoven fabric layer, and an adhesive layer are laminated,
The thermoplastic resin layer is a polyolefin having a layer thickness of 10 to 60 μm;
Basis weight of the layer nonwoven layer is a thermoplastic elastomer nonwoven fabric is 40 to 120 g / ^{m 2,}
The basis weight of the pressure-sensitive adhesive layer is 15 to 300 g / m ² ,
Stretch adhesive sheet stretch adhesive sheet obtained is characterized in that permanent set after being stretched to 100% is 20% to 80% a and the elongation at break of 200% or more. The extensible adhesive sheet according to claim 1 , wherein the extensible adhesive sheet has a stress at 10% elongation of 5 N / cm or less and a maximum point stress of 10 N / cm or more.   The extensible adhesive sheet according to claim 1 or 2, wherein the adhesive layer comprises an acrylic adhesive. Any building member joining the adhesive tape comprising a stretchable pressure-sensitive adhesive sheet according to claims 1-3.