JP2017061590A - Coating composition, sheet having coating layer and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composition capable of forming a coating layer having tack-free property without impairing the texture of a sheet substrate.SOLUTION: There is provided a composition for forming a coating layer having tack-free property on a sheet substrate, wherein the composition comprises an acrylic resin having a glass transition temperature of -20°C to -55°C and/or an urethane resin and thermally expandable microcapsules, the ratio of the thermally expandable microcapsules to a solid content in the composition is 1.3 to 5 wt.% and the thermally expandable microcapsules preferably have an average particle diameter of 5 to 25 μm.SELECTED DRAWING: None

Description

  The present invention relates to a composition for forming a coating layer on a sheet substrate such as a fabric or a plastic film, a sheet having a coating layer comprising the composition, and a method for producing the sheet.

  Conventionally, a back coating process for a sheet substrate has been performed for the purpose of imparting flame retardancy to a sheet substrate such as a fabric, maintaining the strength of a seam, and hardening a structure to prevent fraying of fibers. Has been done.

  The coating processing composition is a liquid resin composition, and a composition containing additives such as a thickener and a flame retardant in addition to a base resin and a solvent is used.

  Sheets that have been back-coated are generally rolled and transported and stored, but because the coating layer is prone to tack (adhesion / adhesiveness), the sheets and sheets are opened when the roll is opened. There is a problem that it takes time and effort to peel off. Similarly, even when 10 to 20 sheets are stacked and cut, if there is a tack, there is a problem that it takes much time to peel off each sheet.

As a method for reducing tack, a method of adding a filler (for example, an inorganic filler such as aluminum hydroxide or calcium carbonate) to the coating composition can be considered, but when such a filler is added, the coating layer becomes hard and heavy. Therefore, there is a problem that the texture of the sheet is deteriorated. In order to soften the texture, it is effective to use a resin having a low glass transition point. However, when a resin having a low glass transition point is used, there is a problem that tack tends to increase.
Therefore, there is a problem that it is difficult to form a coating layer having tack-free properties without impairing the texture of the sheet base material.

  Conventionally, there have been many inventions in which a special resin layer is provided on a fiber fabric substrate for the purpose of preventing slippage (for example, Patent Document 1), and for the purpose of preventing the occurrence of curling of a laminate. Although there is an invention that provides a resin layer (Patent Document 2), a technique for increasing the strength of the sheet base material or preventing tackiness of the coating layer for imparting flame retardancy to the sheet base material has been sufficiently developed. Absent.

JP 2002-13080 A JP 2003-285383 A

  Therefore, the present invention is a coating composition capable of forming a coating layer having tack-free properties without impairing the texture of the sheet substrate, and a coating layer comprising the composition formed on one side of the sheet substrate. It is an object to provide a sheet.

  As a result of repeated studies to solve the above problems, the present inventors have used a composition in which a resin having a glass transition point in a specific range and a thermally expandable microcapsule are mixed at a predetermined ratio, and a sheet. By coating the base material, the tack of the coating layer was suppressed and a sheet having a soft texture was successfully obtained, thereby completing the present invention.

The composition of the present invention is a composition for forming a coating layer having tack-free properties on a sheet substrate,
An acrylic resin and / or urethane resin having a glass transition point of −20 ° C. to −55 ° C. and a thermally expandable microcapsule,
The ratio of the thermally expandable microcapsule to the solid content in the composition is 1.3 to 5% by weight.

  The average particle diameter of the thermally expandable microcapsule is preferably 5 to 25 μm.

  The coating composition further includes a flame retardant, and the ratio of the resin to the solid content in the composition is preferably 30 to 50% by weight, and the ratio of the flame retardant is preferably 45 to 65% by weight. .

The present invention also relates to a method for producing a sheet having a tack-free coating layer using the coating composition,
Applying the coating composition to a thickness of 10 to 30 μm on one side of a sheet substrate;
The method includes a step of heat-treating the sheet base material on which the coating layer is formed to expand the thermally expandable microcapsules contained in the composition so as to protrude from the surface of the coating layer.

  The sheet base material is preferably a fabric having a thickness of 0.2 to 3.0 mm.

The present invention also relates to a sheet in which a coating layer having tack-free properties is formed on one side of a sheet substrate.
The coating layer contains an acrylic resin and / or urethane resin having a glass transition point of −20 ° C. to −55 ° C., and a thermally expandable microcapsule,
The ratio of the thermally expandable microcapsule to the solid content constituting the coating layer is 1.3 to 5% by weight, and the thermally expandable microcapsule protrudes from the surface of the coating layer to form irregularities. Features.

  The coating layer formed by the coating composition according to the present invention has a soft texture because it contains a resin having a glass transition point in the range of -20 ° C to -55 ° C. Further, since the resin is selected from acrylic resin and urethane resin, a soft coating layer can be maintained, which is suitable for fabric use. Furthermore, after the coating composition is applied to the sheet base material, the sheet is heat-treated, whereby the thermally expandable microcapsules in the composition expand, so that the surface of the coating layer can be uneven. . For this reason, a tack suppression effect is acquired by reducing the contact area of a coating layer and the substance put on it.

FIG. 1 is a low-vacuum scanning electron microscope (low-vacuum SEM) photograph of a cross section of a plastic sheet on which a coating layer is formed by the coating composition of the present invention.

  The coating composition of the present invention is particularly suitable as a back coating composition for thin sheet substrates. Although the texture of a thin sheet base material is likely to deteriorate due to the back coating process, the coating composition of the present invention has a coating layer that does not impair the soft texture on such a thin sheet base material. Can be formed.

Examples of the sheet base material include fabrics (for example, fabrics such as woven fabrics and knitted fabrics made of synthetic fibers such as polyester fibers and nylon fibers, or natural fibers such as cotton and wool), polyethylene, polypropylene, and the like. A plastic sheet made of a synthetic resin can be mentioned. In the case of a fabric, a preferable thickness is 0.2 to 3.0 mm, a more preferable thickness is 0.3 to 1.5 mm, and a particularly preferable thickness is 0.4 to 1.2 mm. In the case of a plastic sheet, a preferable thickness is 10 to 30 μm.
A particularly preferable sheet base material is a cloth made of polyester fiber having a thickness of 0.3 to 1.5 mm (weight per unit area: 150 to 350 g / m ² ), particularly a thickness of 0.4 to 1.2 mm (per unit weight of 200 to 300 g / m ² ). is there.

The coating composition of the present invention includes a resin having a glass transition point of −20 ° C. to −55 ° C. selected from acrylic resins and urethane resins. When the glass transition point is lower than −20 ° C., the coating layer becomes hard and the texture of the sheet tends to become hard. A more preferable glass transition point of the resin is −30 ° C. to −50 ° C., and particularly preferably −30 ° C. to −45 ° C.
As such acrylic resins and urethane resins, those commercially available as acrylic resins or urethane resins for coating can be used, for example, as a new coat from Shin-Nakamura Chemical Co., Ltd. Commercially available acrylic resins and urethane resins sold under the trade name Superflex from Daiichi Kogyo Seiyaku Co., Ltd. can be used.

  The coating composition of the present invention includes thermally expandable microcapsules. Thermally expandable microcapsules are usually composed of an outer shell (shell) made of a thermoplastic resin and a volatile liquid (usually low-boiling liquid hydrocarbons such as isobutane and isopentane) contained therein. By heating, the thermoplastic resin constituting the outer shell is softened, the liquid contained therein is volatilized, the internal pressure is increased, and the microcapsule expands (becomes a balloon). Basically, microcapsules do not rupture and their weight is the same before and after expansion. As such thermally expandable microcapsules, commercially available products can be used, for example, those sold under the name Matsumoto Microsphere from Matsumoto Yushi Seiyaku Co., Ltd. can be used. Such microcapsules are conventionally used as an anti-slip agent for carpets and the like, but the present inventor has found that a tack prevention effect can be obtained by using such microcapsules at a predetermined ratio. It was.

  The coating composition of the present invention contains unexpanded microcapsules. After coating the composition on a sheet substrate, the microcapsules are expanded by heating treatment, and the microcapsules are separated from the surface of the coating layer. By projecting the part, an uneven surface can be formed. As a result, even when this sheet is rolled up after coating or when a plurality of sheets are stacked, the contact area between the sheets is reduced, so that tack is suppressed and a so-called tack-free state is achieved. it can.

As the microcapsules, the average particle diameter when not expanded is equal to or less than the coating thickness when forming the coating layer (thickness before volatilizing the solvent), and the average particle diameter after expansion is the thickness of the coating layer (after solvent volatilization) It is more preferable to select a microcapsule that is 20 μm or more larger than (thickness). By selecting thermally expandable microcapsules having such an average particle size, coating becomes easy and tack can be sufficiently suppressed.
Whether the average particle diameter after expansion is 20 μm or more larger than the thickness of the coating layer depends on the thickness of the coating layer (after solvent volatilization) formed using a composition not containing thermal expansion microcapsules and thermal expansion. It can be judged from the average particle diameter after expansion (or thermal expansion coefficient, etc.) described in the product description of the functional microcapsule. Alternatively, using a composition containing a thermally expandable microcapsule and a composition not containing a thermally expandable microcapsule, respectively, after forming a coating layer on a sheet substrate under the same conditions and drying, the cross-sections are electronic Convex part of coating layer (concave / convex layer) containing thermally expandable microcapsules compared to the average thickness of the coating layer not containing thermally expandable microcapsules as observed with a microscope (SEM, low vacuum SEM, SEM-EDX, etc.) It can be judged by whether the average value of the heights of these is larger by 20 μm or more. Preferably, the average particle diameter after expansion is preferably 30 μm or more larger than the thickness of the coating layer (after solvent volatilization). Usually, since the coefficient of thermal expansion varies depending on the heating temperature, it is also possible to control the average particle diameter after thermal expansion by adjusting the heating temperature.

The average particle diameter of the microcapsules used in the present invention when not expanded and after expansion varies depending on the coating thickness when forming the coating layer and the thickness of the coating layer after drying. The average particle diameter is preferably 5 to 25 μm, more preferably 8 to 22 μm, and particularly preferably 10 to 20 μm.
The microcapsules preferably have an average particle size of 30 μm or more after expansion, more preferably 35 μm or more, and particularly preferably 40 μm or more. The upper limit of the average particle diameter after expansion is suitably 80 μm or less, more preferably 70 μm or less.
In the present invention, the average particle size of the microcapsules contained in the composition is determined by observing the microcapsules in the composition with an electron microscope such as SEM and all microcapsules contained in a randomly extracted field of view photograph (at least 10 or more) can be measured, and the arithmetic average can be calculated. If you want to measure the average particle size before expansion, after drying the composition at a temperature that does not cause thermal expansion, if you want to measure the average particle size after expansion, after drying the composition at a temperature at which thermal expansion occurs Measurement can be performed. If the composition contains particulate matter other than microcapsules, an electron microscope (SEM) equipped with an energy dispersive X-ray elemental analyzer (EDX) that can distinguish microcapsules from other particulate matter. -EDX etc.) can be used.
In addition, the particle diameter of the microcapsule after being expanded attached to the fabric is estimated from a part of the microcapsule protruding from the fabric surface by observing a cross section of the fabric with an electron microscope as shown in FIG. Therefore, the average particle diameter can be obtained by calculating the diameter of all microcapsules (at least 10 or more) included in the randomly extracted field of view photograph and calculating the arithmetic average thereof.
As the electron microscope, for example, a low vacuum SEM (desk microscope, Miniscope TM3030, etc.) or SEM-EDX (SEM / EDX III TypeN, etc.) sold by Hitachi High-Technologies Corporation can be used.

  The composition of this invention contains liquid agents (solvent), such as water and an organic solvent, other than the said resin and a thermally expansible microcapsule. The proportion of the solvent in the total amount of the composition is preferably 40 to 70% by weight, and more preferably 45 to 65% by weight. A preferred composition of the present invention is a water-based composition, wherein 80% by weight or more, more preferably 90% by weight or more of the solvent contained in the composition comprises water.

  Moreover, the composition of this invention can contain a flame retardant, a crosslinking agent, a thickener, a dispersing agent, a pigment, etc. A preferred composition is a composition comprising a flame retardant and a thickener. As the flame retardant, an alkylphosphinic acid metal salt such as aluminum trisdiethylphosphinate, aluminum trismethylethylphosphinate or aluminum trisdiphenylphosphinate is preferable.

  The composition of the present invention preferably contains the microcapsules in an amount of 1.3 to 5.0% by weight when the solid content of the composition is 100% by weight, and preferably 1.5 to 4.0% by weight. %, More preferably 2.0 to 3.0% by weight. If the amount of the microcapsules is too small, the tack-inhibiting effect cannot be sufficiently exerted. If the amount is too large, foaming of the coating layer proceeds, resulting in a thick sheet having a high thickness and high bending resistance.

  In addition, the composition of the present invention preferably contains 30 to 50% by weight, particularly 35 to 45% by weight of the resin selected from the acrylic resin and the urethane resin in terms of the solid content described above. It is preferable to contain 45 to 65% by weight (preferably alkylphosphinic acid metal salt), particularly 50 to 60% by weight. Such a composition is useful as a flame retardant coating agent for imparting high flame retardancy to a sheet substrate.

  In the manufacturing method of the sheet | seat of this invention, 10 micrometers-30 micrometers are preferable, and, as for the coating thickness at the time of apply | coating the coating composition of this invention to a sheet | seat base material, 15-25 micrometers is more preferable. The coating composition can be applied using a knife coater, comma coater, bar coater, die coater, kiss roll coater, gravure coater or the like.

  The sheet base material that has been subjected to the coating treatment is then subjected to a heat treatment, whereby drying of the coating layer and expansion of the thermally expandable microcapsules occur. The heat treatment is performed at a temperature of 120 to 170 ° C, more preferably 130 to 160 ° C, particularly preferably 145 to 155 ° C. The heating time is about 2 to 10 minutes, particularly about 3 to 7 minutes.

  In the heat treatment step, due to the volatilization of the solvent from the coating layer, the thickness of the coating layer decreases, and at the same time, the thermally expandable microcapsule expands. A part of the protrusion protrudes and an uneven surface is formed. As described above, since a rough surface having a difference between the concave and convex portions of about several tens of microns is formed, tack on the surface of the coating layer is reduced, and a so-called tack-free state is assumed.

  The term tack-free is generally used in the industry in the sense of low adhesion, and in this specification, tack-free refers to winding a sheet having a coating layer made of the composition of the present invention into a roll, When several to several tens of sheets are stacked, it means a state in which the contacted sheets do not adhere to each other and easily peel off. An example of a measure for determining the tack-free property of the composition is a peel strength measured by the method described in Example 1 (in the case of 0 to 30 g / 50 mm, it can be evaluated as tack-free). According to the present invention, a peel strength of about 0 to 5 g / 50 mm can be realized.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to an Example.

[Example 1]
In order to suppress tackiness of the coating composition, a coating composition was prepared using three types of acrylic resins having different glass transition points (Tg), a thickener, and an aqueous ammonium solution. In addition, an inorganic filler, a crosslinking agent or a thermally expandable microcapsule was added to the composition, and the influence on tack and texture was observed.
Newcoat KK-54-4 was used as the resin with Tg = + 8 ° C., Newcoat FH-4502 was used as the resin with Tg = −45 ° C., and Plaster EH was used as the resin with Tg = −55 ° C. Shin-Nakamura Chemical Co., Ltd.). Also, blocked isocyanate (Nikka Chemical Co., Ltd./NK Assist FU) was used as a crosslinking agent, and an acrylic polymer (Shin Nakamura Chemical Co., Ltd./Vanazol KB-660) which was alkaline and thickened was used as a thickener. Matsumoto Microsphere F-50 (Matsumoto Yushi Seiyaku Co., Ltd.) was used as the thermally expandable microcapsule.

[Tack evaluation method]
Each resin composition was applied onto a glass plate using a bar coater (manufactured by Daiichi Rika Co., Ltd./No. 10) to form a coating layer having a coating thickness of about 23 μm. (For a composition that does not contain thermally expandable microcapsules, the thickness of the coating layer after drying is about 10 μm). Thereafter, a polypropylene film (PP film) having a width of 50 mm × length of 250 mm × thickness of 10 μm was placed on the coating layer, and a 500 g stainless steel cylinder having a diameter of 40 mm × width of 50 mm was placed thereon, and the length of the PP film After 10 reciprocations along the length direction, the PP film was peeled off from the coating layer at a tensile speed of about 200 mm / min using a weight measuring machine (AIKOH ENGINEERING / MODEL RZ-5). The average value of the peel strength was measured, and the case where the peel strength was in the range of 0 to 30 g / 50 mm was determined to be tack-free.

[Texture evaluation method]
Each resin composition was applied to one side of a fabric having a basis weight of 280 g / m ² (thickness: about 0.5 mm) made of polyester fiber to form a back coating layer, and the texture was checked by checking the hand. Compared to fabrics (blanks) that do not have a back coating layer, X is when the texture is clearly hard, △ is when the texture is slightly hard, ○ is when the texture is almost equivalent, and the texture is greater than the blank. When it became soft, it evaluated as ◎.

  The results are shown in Table 1. In addition, the numerical value in the table | surface regarding each composition is a weight part (weight part containing liquids, such as a solvent) of each chemical | medical agent, and the numerical value in a parenthesis is weight% when the total weight of solid content is 100%. (The same applies to Tables 2 to 4).

As can be seen from Table 1-1, the resin with Tg of + 8 ° C. had a tack measurement value of 0, but the texture became harder (1). Resins with Tg of −45 ° C. and −55 ° C. had a good texture but had a very large tack (2 and 3). When a resin having a Tg of + 8 ° C. and a resin having a Tg of −55 ° C. are mixed in various proportions (4 to 6), if the proportion of the resin having a Tg of + 8 ° C. is increased, the target tack value (0 to 30 g / 50 mm) could be achieved, but in all cases the texture was poor and the desired coating layer could not be obtained.
When an inorganic filler (aluminum hydroxide or calcium carbonate) was added (7 to 14), a tendency for the tack to decrease with an increase in the amount added was observed, but the target value for tack was achieved even when 10 parts by weight was added. (10 and 14), and as the amount of inorganic filler added increased, the texture worsened (heavier and harder).
Further, as can be seen from Table 1-2, when the cross-linking agent was added (15 to 17), as the addition amount increased, tack tended to decrease, but the target value of tack could not be achieved.

  On the other hand, when the thermally expandable microcapsule is added, the content in terms of solid content is 1.4% by weight or more (compositions 20 to 25), the tack falls within the target value range, and good A composition capable of maintaining the texture could be obtained.

  One side of a plastic (polyester) sheet was coated with the composition (22) to which thermally expandable microcapsules were added, and the cross section was observed with a low vacuum scanning electron microscope (Hitachi tabletop microscope Miniscope TM3030). As described above, it was confirmed that many irregularities of several tens of microns were formed on the surface of the coating layer. For this reason, when using thermally expandable microcapsules, the contact area with the sheet stacked thereon is reduced due to the unevenness of the coating layer (because it is point contact rather than surface contact), so that tack is suppressed. It is thought.

[Example 2]
In order to confirm that the microcapsule expands due to heat and protrudes from the surface of the coating layer to obtain an anti-tacking effect, the microcapsule expansion ratio is changed (that is, the particle size of the microcapsule after expansion is changed). The impact of the change) on tack prevention was examined.
Specifically, in order to change the expansion ratio of the microcapsules, a coating layer is formed on the glass plate by the same method as in Example 1 except that the heating temperature by the gear oven is changed, and the same method as in Example 1. Tack was measured with. Each component used is the same as in Example 1. The used microcapsules begin to expand at around 100 ° C., and the expansion ratio increases with increasing temperature from 140 to 150 ° C. The peak expansion coefficient is about 4.5 at 140-150 ° C. The results are shown in Table 2.

  As is apparent from Table 2, the tack decreased as the expansion ratio of the microcapsule increased from about 1 to about 3, and when the expansion ratio increased to about 3 or more (28 to 31), the tack decreased from 2 to 3 g / 50 mm. It turned out to decrease. From this, it was confirmed that the microcapsules sufficiently protrude from the surface of the coating layer to form an uneven surface, thereby reducing the tack.

[Comparison experiment]
Example 1 shows that the target tack value cannot be achieved even when aluminum hydroxide having an average particle diameter of 1 μm is used, but aluminum hydroxide having a particle diameter larger than the dried thickness (about 10 μm) of the coating layer. Since some of the aluminum hydroxide particles protrude from the coating layer, irregularities are formed on the surface of the coating layer, and it is thought that the tack target value can be achieved. All were manufactured by Nippon Light Metal Co., Ltd., and a coating layer was formed by the same method as in Example 1. The tack and texture were evaluated by the same method as in Example 1. When aluminum hydroxide having an average particle diameter of 108 μm was used, the aluminum hydroxide was caught by the bar coater and could not be coated. The results are shown in Table 3.

  As can be seen from Table 3, when aluminum hydroxide having an average particle size of 1 μm was used, the tack target value could not be achieved even when the addition amount was increased to 10 parts by weight (35), but the average particle size was 12. When 7.5 parts by weight and 10 parts by weight of aluminum hydroxide of 6 to 55 μm were used (37, 38, 40, 41, 43, 44), it was found that the tack target value (0 to 30 g / 50 mm) could be achieved. . However, it was found that the fabrics back-coated with these compositions (37, 38, 40, 41, 43, 44) all deteriorated in texture, and the desired product could not be obtained.

[Example 3]
Aluminum hydroxide or thermally expandable microcapsules were added to the flame retardant coating composition, and the influence on the coating amount and bending resistance was examined.

  A resin having a Tg of −30 ° C. (DIC Corporation / Boncoat AB-901) is used as the acrylic resin, and a polyoxyalkylene alkyl ether surfactant (Sanyo Chemical Industries, Ltd./Sannonic FN-140) is used as the surfactant. ), Alkylphosphinic acid metal salt (Nobuha Corporation / SY-TC) as a flame retardant, methyl hydroxyethyl cellulose (Shin-Etsu Chemical Co., Ltd./Tyroze) as a thickener, and Matsumoto Micro as a thermally expandable microcapsule. Sphere F-50 (Matsumoto Yushi Seiyaku Co., Ltd.) was used. As aluminum hydroxide, the thing of each particle size currently sold from Nippon Light Metal Co., Ltd. was used.

[Preparation of flame retardant coating composition]
Add surfactant and flame retardant to acrylic resin, stir well, add water, and increase to about 35,000 mPa · S (BH viscometer, rotor No. 5 × 4 rpm) with thickener. A basic composition (48) was prepared by sticking. Other compositions (49-58) were prepared by adding the heat-expandable microcapsules or aluminum hydroxide shown in Table 4 after the basic composition was prepared and stirring well.

[Back coating processing]
Using a knife coat, each composition shown in Table 4 was coated on one side of a sheet base material (polyester fabric made of polyester having a thickness of about 0.5 mm and a basis weight of about 280 g / m ² ). Dry for 30 seconds. The coating thickness of the coating layer was about 20 μm. The thickness after drying of the coating layer comprising the basic composition (48) was about 10 μm.

[Bending test method]
The coated fabric was cut into 20 mm × 200 mm to prepare test pieces, and the bending resistance was measured using a bending resistance tester (corresponding to 45 ° cantilever method). Specifically, when the test piece is placed on the horizontal platform of the test machine so that the coating surface is down, the test piece is slid in the slope direction at a constant speed, and one end of the test piece comes into contact with the slope. The moving distance of the other end was read with a scale, and the distance (mm) was defined as the bending resistance.

As can be seen from Table 4, the composition (49.50) containing the thermally expandable microcapsules had a coating amount smaller than that of the basic composition. This is presumably because the coating amount (weight) is slightly reduced even when the composition is applied with the same thickness because the composition includes thermally expandable microcapsules with a small specific gravity. On the other hand, when a composition containing aluminum hydroxide having a high specific gravity is used, the coating amount increases even if the coating thickness during the coating process is the same. In addition, when aluminum hydroxide having an average particle diameter of 55 μm or 108 μm is used, it is impossible to perform uniform coating due to poor knife passage during coating (aluminum hydroxide particles get caught on the coating knife). Therefore, the coating amount and the bending resistance were not measured.
Regarding the bending resistance, the composition to which aluminum hydroxide was added tended to be higher than the composition to which thermally expandable microcapsules were added.

As described above in the description of Table 3, when 7.5 to 10 parts by weight of aluminum hydroxide having a large average particle diameter was used, it was confirmed that although the target value of tack could be achieved, the texture deteriorated. The deterioration of the texture is considered to be caused by the fact that the coating amount increases (resulting in an increase in sheet weight) due to the high specific gravity of aluminum hydroxide, and that aluminum hydroxide tends to increase the bending resistance. . Compared to this, the composition to which the thermally expandable microcapsules are added has a smaller coating amount than the basic composition, and since the degree of increase in the bending resistance is low, it is considered that the texture of the sheet is hardly impaired.
Furthermore, it was found that when the average particle size of aluminum hydroxide was 30 μm or more, the coating knife passing property deteriorated and streaks or the like were generated on the coating surface. On the other hand, in the case of the thermally expandable microcapsule, the average particle diameter at the initial stage (during coating) is smaller than the coating thickness of the coating layer, so that the coating layer can be formed without being caught by the coating knife. The microcapsules can be expanded to produce an uneven surface. For this reason, the use of thermally expandable microcapsules was very suitable for achieving both good coating properties and tack-free.

[Example 4]
The composition shown in Table 5 was prepared, and the composition was coated on one side of a sheet substrate (a polyester fabric having a thickness of about 0.5 mm and a basis weight of about 280 g / m ² ) using a knife coat at 150 ° C. Heat treatment was performed for 2 minutes and 30 seconds.
The acrylic resin, flame retardant, thermally expandable microcapsule, and surfactant used are the same as in Example 3.

Ten sheets of the obtained fabric were stacked and cut into a size of 7 cm × 30 cm using a hydraulic clicker IOC-20B manufactured by Iino Iron Works. After cutting, the overlapping fabrics were easily peeled from each other, and the time required for the peeling process could be significantly shortened.
Further, the texture of the obtained fabric was good. Furthermore, the fabric has flame retardancy that satisfies the standards defined in the combustion test of automobile interior materials according to FMVSS 302 (Federal Motor Vehicle Safety Standards), and the composition of the present invention has good texture and tack-free properties. In addition, it has been found that excellent flame retardancy can be achieved.

  The coating composition according to the present invention is very useful because it is easy to coat and can achieve both soft texture and tack-free.

Claims (6)

A composition for forming a coating layer having tack-free properties on a sheet substrate,
An acrylic resin and / or urethane resin having a glass transition point of −20 ° C. to −55 ° C. and a thermally expandable microcapsule,
A composition for coating, wherein a ratio of the thermally expandable microcapsule to a solid content in the composition is 1.3 to 5% by weight.   The composition of Claim 1 whose average particle diameter of the said thermally expansible microcapsule is 5-25 micrometers.   The coating composition further comprises a flame retardant, the ratio of the resin to the solid content in the composition is 30 to 50% by weight, and the ratio of the flame retardant is 45 to 65% by weight. 2. The composition according to 2. A method for producing a sheet comprising a coating layer having tack-free properties using the coating composition according to any one of claims 1 to 3,
Applying the coating composition to a thickness of 10 to 30 μm on one side of a sheet substrate;
A manufacturing method comprising a step of heat-treating a sheet base material on which a coating layer is formed to expand the thermally expandable microcapsules contained in the composition to protrude from the surface of the coating layer .   The manufacturing method of Claim 4 whose said sheet | seat base material is a fabric of thickness 0.2-3.0mm. A sheet in which a coating layer having tack-free properties is formed on one side of a sheet base material,
The coating layer contains an acrylic resin and / or urethane resin having a glass transition point of −20 ° C. to −55 ° C., and a thermally expandable microcapsule,
The ratio of the thermally expandable microcapsule to the solid content constituting the coating layer is 1.3 to 5% by weight, and the thermally expandable microcapsule protrudes from the surface of the coating layer to form irregularities. Characteristic sheet.