JP4839090B2 - Removable pressure-sensitive recording paper - Google Patents

Description

  The present invention relates to a release agent (silicone oil) used for preventing toner transfer to a heat roll as a fixing roll when printing with an electrostatic recording type (electrophotographic type) heat roll fixing type printer. The present invention is to provide a releasable pressure-sensitive recording sheet that is less likely to cause a decrease in adhesive strength due to adhesion of the pressure-sensitive adhesive layer surface.

  In recent years, private postcards have been widely used as means for notifying personal information such as savings, balances, etc. to individual individuals from banks, credit companies, insurance companies, government agencies, and the like. After applying a pressure sensitive adhesive on the base material for confidential postcards, common information is offset printing, gravure printing, etc. [oxidation polymerization ink type, ultraviolet (UV) curable ink type], personal information is electrophotographic and After printing by a non-impact printer such as an ink jet method, the printing surfaces are bonded together by applying an appropriate pressure, and after being mailed to each individual, information can be obtained by re-peeling.

  However, in offset printing, etc., an ultraviolet lamp is used for fixing the ink. On the other hand, high-speed electrophotographic printers include a heat roll fixing printer that performs toner fixing with a high heat (180 to 220 ° C.) heat roll. The heat roll is supplied with silicone oil on the roll surface for the purpose of preventing offset printing ink and toner adhesion. The pressure-sensitive adhesive layer is deteriorated by heat, resulting in a problem that the adhesive strength is lowered. As a means for solving this, styrene-butadiene (which has little thermal deterioration as a resin in place of the methyl methacrylate graft copolymer natural rubber adhesive) It has been proposed to use (SBR) resin or ethylene-vinyl acetate resin (for example, see Patent Documents 1 to 3).

  However, in the case of heat roll fixing type printers for electrophotographic printing, the adhesive strength reduction is not only the deterioration of the pressure-sensitive adhesive layer due to heat, but also supplied as a release effect on the surface of the fixing roll to prevent toner transfer to the fixing roll. Adhesive strength of the silicone oil applied to the surface of the pressure-sensitive adhesive layer is greatly reduced, and peeling off during mailing may cause problems in practical use in terms of confidentiality.

JP 2000-318353 A (0001, paragraphs 0008 to 0025) JP 2001-335762 (paragraphs 0001 and 0006 to 0033) Japanese Patent Laying-Open No. 2003-160764 (paragraphs 0001 and 0007 to 0015)

  An object of the present invention is to provide a pressure-sensitive adhesive of a release agent (silicone oil) used for preventing toner transfer to a heat roll as a fixing roll when printing with an electrophotographic heat roll fixing printer. The present invention is to provide a releasable pressure-sensitive recording paper that is less likely to cause a decrease in adhesive strength due to adhesion of the layer surface.

As a result of intensive studies to solve the above problems, the present inventors have found that the pressure-sensitive adhesive layer is a pressure-sensitive adhesive composition comprising an adhesive and a fine particle filler. Particulate filler having a contact angle (ASTM D 5725) 10 seconds or less after dropping of silicone oil on the surface of the agent layer is 60 ° or less, the particulate filler has a specific surface area of 150 to 550 m ² / g, and an oil absorption of 80 to 400 mL / 100 g. The adhesive is selected from a natural rubber adhesive or a synthetic adhesive, the natural rubber adhesive is a resin obtained by graft polymerization of 25% methyl methacrylate, and the synthetic adhesive is a styrene-butadiene copolymer. polymer der is, Heading to be solved by the adhesive to the particulate filler 100 parts by weight to obtain a peelable crimped recording paper which is characterized by containing 100 to 180 parts by weight It was.

  That is, the present invention relates to a releasable pressure-sensitive adhesive recording paper having a pressure-sensitive adhesive layer on at least one side which does not exhibit tackiness and adhesiveness at normal temperature and normal pressure but exhibits adhesiveness when pressed and can be peeled after pressure bonding. The pressure-sensitive adhesive layer is a layer made of a pressure-sensitive adhesive composition comprising an adhesive and a fine particle filler, and the contact angle 10 seconds after dropping of the silicone oil on the pressure-sensitive adhesive layer surface is 60 °. The present invention provides a releasable pressure-sensitive recording sheet characterized by the following.

The present invention also provides a releasable pressure-sensitive recording sheet, wherein the fine particle filler is a fine particle filler having a specific surface area of 150 to 550 m ² / g and an oil absorption of 80 to 400 ml / 100 g. .

  Furthermore, the present invention provides a releasable pressure-sensitive recording paper, wherein the adhesive contains 50 to 200 parts by mass with respect to 100 parts by mass of the fine particle filler.

  In a releasable pressure-sensitive adhesive recording sheet having a pressure-sensitive adhesive layer on at least one side, which does not exhibit tackiness and adhesiveness at normal temperature and normal pressure according to the present invention, exhibits adhesiveness when pressed, and can be peeled after pressure bonding. The pressure-sensitive adhesive layer is a layer made of a pressure-sensitive adhesive composition comprising an adhesive and a fine particle filler, and the contact angle after 10 seconds of dropping the silicone oil on the surface of the pressure-sensitive adhesive layer is 60 ° or less. This makes it possible to bond after applying silicone oil, which is a release agent used to prevent toner transfer to the heat roll when printing with an electrostatic recording (electrophotographic) heat roll fixing printer. When used as a confidential postcard, the strength reduction is small, and a releasable pressure-sensitive recording paper satisfying adhesion and removability is obtained.

BEST MODE FOR CARRYING OUT THE INVENTION

  The present invention will be described in detail below, but the present invention is not limited to these embodiments.

The present invention is greatly characterized in that the contact angle 10 seconds after dropping the silicone oil on the surface of the pressure-sensitive adhesive layer is 60 ° or less. To achieve this contact angle, a fine particle filler having a specific surface area of 150 to 550 m ² / g and an oil absorption of 80 to 400 mL / 100 g contributes to the pressure-sensitive adhesive layer.

  In the releasable pressure-sensitive recording paper of the present invention coated with the pressure-sensitive adhesive layer, 3 μL of silicone oil is dropped on the pressure-sensitive adhesive layer surface, and the contact angle after 10 seconds (ASTM D 5725) is 60 ° or less. It is very important that Incidentally, when the contact angle exceeds 60 °, the wetting of the silicone oil is deteriorated and the amount of adhesion to the surface of the pressure-sensitive adhesive layer is reduced, but the ink setting property at the time of offset printing is lowered. The contact angle is preferably 50 ° or less, and there is no particular lower limit, but 10 ° or more is preferable.

  The contact angle is measured using a releasable pressure-sensitive recording paper before the pressure-bonding process. By passing through the pressure bonding step, the pressure-bonded surface is re-peeled to roughen the pressure-sensitive adhesive layer surface. In addition, for example, even on a non-crimped surface such as an address surface, the physical properties such as the smoothness and air permeability of the pressure-sensitive adhesive layer surface change due to the pressure in the pressure-bonding process. Are different pressure sensitive adhesive layer surfaces.

  The composition of the adhesive used in the present invention is not particularly limited. Modified natural rubber is used as a natural rubber-based adhesive, and styrene-butadiene rubber, acrylonitrile-butadiene rubber, and ethylene-vinyl acetate copolymer are used as synthetic adhesives. Examples thereof include resins, acrylic ester resins, vinyl chloride resins, vinylidene chloride resins, and the like.

<Natural rubber adhesive>
The natural rubber adhesive of the present invention is not particularly limited as long as it is a natural rubber derivative resin. However, a resin obtained by graft polymerization of at least one unsaturated monomer selected from methyl methacrylate, styrene, and acrylonitrile on natural rubber is used. preferable. In particular, a coating solution in which a natural rubber derivative obtained by graft-polymerizing 15 to 40 parts by mass of at least one unsaturated monomer to 100 parts by mass of a solid content of natural rubber comprises a stable adhesive strength and a pressure-sensitive adhesive composition. It is preferable because of its excellent mechanical stability.

<Synthetic adhesive>
The synthetic adhesive used in the present invention includes styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber, ethylene-vinyl acetate copolymer resin, acrylate ester resin, vinyl chloride resin, vinylidene chloride resin, polyisobutylene, Polyvinyl ether, nitrile butadiene rubber or the like or, in some cases, blends thereof are preferred.

The particulate fillers used in the present invention, a specific surface area 150~550m ² / g, preferably 250~500m ² / g and an oil absorption of 80~400ml / 100g, preferably inorganic meet 150~350ml / 100g or Any known organic fine particle filler can be appropriately selected and used. As the fine particle filler, inorganic and organic pigments can be used. For example, zinc oxide, titanium oxide, zeolite, calcium carbonate, clay, aluminum oxide, silica, alumina, γ-alumina, colloidal silica, aluminosilicate and the like as inorganic pigments, and wheat starch, plastic pigment, polystyrene resin as organic pigments, Examples thereof include styrene resins such as acrylonitrile-butadiene-styrene resin, acrylonitrile-styrene resin, and styrene-butadiene block copolymer, polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, and cyclopentadiene-based petroleum resins. These fine particles can be used alone or in combination of two or more. Among these, it preferred inexpensively available inorganic fine particles, silica are used in various applications, particularly synthetic silica preferred.

  The amount of the adhesive in the pressure-sensitive adhesive layer is 50 to 200 parts by weight, preferably 100 to 170 parts by weight with respect to 100 parts by weight of the fine particle filler in consideration of the balance of performance such as silicone oil absorbability and adhesive strength. It is desirable to blend at a ratio of When the adhesive compounding amount is less than 50 parts by mass, the adhesive strength of the pressure-sensitive adhesive layer may be weak, and when it exceeds 200 parts by mass, the fine particle filler is covered, and the silicone oil absorbability is reduced. Adhesive strength can be greatly reduced.

  In the pressure-sensitive adhesive layer of the present invention, a pigment dispersant, a thickener, a fluidity improver, an antifoaming agent, a defoaming agent, a dispersing agent, a release agent, a sizing agent, and coloring are added as necessary. Auxiliaries such as dyes, ultraviolet absorbers, antistatic agents, cationic, nonionic or amphoteric surfactants, antioxidants, preservatives, water-resistant agents, pH adjusters and the like can be added.

  The substrate used in the present invention is not particularly limited, but in addition to conventionally known foam paper (uncoated paper), it is coated with fine paper, medium paper, impregnated paper impregnated with various binders and various pigments. Engineered coated paper, art paper, synthetic paper, resin film, non-woven fabric, etc. can be used as the base paper. Among them, the paper base material is preferably used because it is inexpensive. The paper base material may contain waste paper pulp, and the papermaking method is not particularly limited.

The coating method is not particularly limited, and various blade coaters, roll coaters, air knife coaters, bar coaters, gravure coaters, die coaters, curtain coaters and the like are used. Among these, an air knife coater, a bar coater, a gravure coater and the like are preferable. The coating amount is in the range of ^{2 to 20} g / m ² , preferably 3 to 15 g / m ² . The reason why the coating amount is limited to the above range is that if it is less than 3 g / m ² , the ink and silicone oil receiving amount of the offset ink receiving layer and the silicone oil receiving layer is decreased, and the visual aspect such as printing finish is reduced. This is because it is not preferable, and the decrease in the adhesive strength due to the decrease in the silicone oil absorbability is also increased. Moreover, when the coating amount exceeds 15 g / m ² , the visual appearance such as printing is improved and the silicone oil absorbability is improved, but the practicality is inferior from the economical viewpoint, and paper dust is generated. It is easy to do and is not preferable.

[Example]
The present invention is further described in detail using the following examples and comparative examples, but the present invention is not limited to these examples. In addition, all the mass parts of an Example and a comparative example shall show with the numerical value in conversion of solid content.

[Reference Example 1]
For synthetic silica, gel method synthetic amorphous silica (Mizukasil P-78A, specific surface area 360 m ² / g, oil absorption 250 g / 100 ml, manufactured by Mizusawa Chemical Industry Co., Ltd.) 100 parts by mass, natural rubber adhesive methyl methacrylate A coating solution of a pressure-sensitive adhesive composition to be a pressure-sensitive adhesive layer of the present invention was obtained by blending 50 parts by mass of a natural rubber-based adhesive obtained by graft polymerization of 25% of (MMA). Then the coated amount per one surface a coating liquid 1 for the pressure-sensitive adhesive composition on a high-quality paper having a basis weight of 127.9 g / m ² is then applied so that the 10 g / m 2 ^(dry mass) It was dried to form a pressure-sensitive adhesive layer, and a releasable pressure-sensitive recording sheet was obtained. Tables 1 and 2 show the results of evaluation of the obtained releasable pressure-bonded recording paper by a peel strength test, a printability test, and a blocking test.
<Coating liquid 1 of pressure-sensitive adhesive composition>
Synthetic silica (Mizukasil P-78A, specific surface area 360 m ² / g, oil absorption 250 g / 100 ml)
100 parts natural rubber adhesive 50 parts [Example 2]

A releasable pressure-sensitive adhesive recording paper was prepared in the same manner as in Reference Example 1 except that 50 parts of the natural rubber adhesive in the coating liquid 1 of the pressure-sensitive adhesive composition of Reference Example 1 was changed to 200 parts. Example 2 was adopted. Table 1 shows the results of evaluation of the obtained releasable pressure-sensitive recording paper by a peel strength test, a printability test, and a blocking test.

[Reference Example 3]
The natural rubber adhesive of the coating solution 1 of the pressure-sensitive adhesive composition of Reference Example 1 was changed to a styrene-butadiene copolymer adhesive (Lx-110, manufactured by Nippon Zeon Co., Ltd.) which is a synthetic adhesive. A releasable pressure-sensitive recording paper was prepared in the same manner as in Reference Example 1 except that the pressure-adhesive composition coating solution 2 was used, and this was designated as Reference Example 3 . Tables 1 and 2 show the results of evaluation of the obtained releasable pressure-bonded recording paper by a peel strength test, a printability test, and a blocking test.
<Coating liquid 2 of pressure-sensitive adhesive composition>
Synthetic silica (Mizukasil P-78A, specific surface area 360 m ² / g, oil absorption 250 g / 100 ml)
100 parts styrene-butadiene copolymer adhesive 50 parts [Example 4]

Except for changing the reference example 3 of the pressure-sensitive adhesive composition of the coating solution 2 of a styrene-butadiene copolymer adhesive (Lx-110, manufactured by Nippon Zeon Co., Ltd.) 50 parts to 200 parts, the same manner as in Reference Example 3 Thus, a releasable pressure-sensitive recording paper was prepared, and this was designated as Example 4. Table 1 shows the results of evaluation of the obtained releasable pressure-sensitive recording paper by a peel strength test, a printability test, and a blocking test.

[Reference Example 5]
The synthetic silica of the coating liquid 1 of the pressure-sensitive adhesive composition of Reference Example 1 was precipitated from Mizukasil P-78A by precipitation method synthetic amorphous silica (Fine Seal X-37B, specific surface area 290 m ² / g, oil absorption 240 g / 100 ml. , change in Tokuyama Corp.), except for using the coating liquid 3 of the pressure-sensitive adhesive composition, in the same manner as in reference example 1 to create the removability crimping recording paper, which was used as a reference example 5. Table 1 shows the results of evaluation of the obtained releasable pressure-sensitive recording paper by a peel strength test, a printability test, and a blocking test.
<Pressure Sensitive Adhesive Composition Coating Liquid 3>
Synthetic silica (Fine seal X-37B, specific surface area 290 m ² / g, oil absorption 240 g / 100 ml) 100 parts natural rubber adhesive 50 parts

[Reference Example 6]
A releasable pressure-sensitive adhesive recording paper was prepared in the same manner as in Reference Example 1 , except that 50 parts of the natural rubber adhesive in the coating liquid 1 of the pressure-sensitive adhesive composition of Reference Example 1 was changed to 70 parts. To Reference Example 6 . Table 1 shows the results of evaluation of the obtained releasable pressure-sensitive recording paper by a peel strength test, a printability test, and a blocking test.
[Example 7]

A releasable pressure-sensitive adhesive recording sheet was prepared in the same manner as in Reference Example 1 except that 50 parts of the natural rubber adhesive in the coating liquid 1 of the pressure-sensitive adhesive composition of Reference Example 1 was changed to 100 parts. Was taken as Example 2. Table 1 shows the results of evaluation of the obtained releasable pressure-sensitive recording paper by a peel strength test, a printability test, and a blocking test.
[Example 8]

A releasable pressure-sensitive recording sheet was prepared in the same manner as in Reference Example 1 except that 50 parts of the natural rubber adhesive in the coating liquid 1 of the pressure-sensitive adhesive composition of Reference Example 1 was changed to 120 parts. Was taken as Example 8. Table 1 shows the results of evaluation of the obtained releasable pressure-sensitive recording paper by a peel strength test, a printability test, and a blocking test.
[Example 9]

A releasable pressure-sensitive recording sheet was prepared in the same manner as in Reference Example 1 except that 50 parts of the natural rubber adhesive in the coating liquid 1 of the pressure-sensitive adhesive composition of Reference Example 1 was changed to 150 parts. Was taken as Example 7. Table 1 shows the results of evaluation of the obtained releasable pressure-sensitive recording paper by a peel strength test, a printability test, and a blocking test.
[Example 10]

A releasable pressure-sensitive adhesive recording paper was prepared in the same manner as in Reference Example 1 , except that 50 parts of the natural rubber adhesive in the coating liquid 1 of the pressure-sensitive adhesive composition of Reference Example 1 was changed to 180 parts. Was taken as Example 10. Table 1 shows the results of evaluation of the obtained releasable pressure-sensitive recording paper by a peel strength test, a printability test, and a blocking test.
[Reference Example 11]

Except for changing the reference example 3 of the coating liquid 2 for styrene-butadiene copolymer adhesive of the pressure-sensitive adhesive composition (Lx-110, manufactured by Nippon Zeon Co., Ltd.) 50 parts to 70 parts, the same manner as in Reference Example 3 Thus, a releasable pressure-sensitive recording paper was prepared and used as Reference Example 11 . Table 1 shows the results of evaluation of the obtained releasable pressure-sensitive recording paper by a peel strength test, a printability test, and a blocking test.
[Example 12]

Except for changing the reference example 3 of the coating liquid 2 for styrene-butadiene copolymer adhesive of the pressure-sensitive adhesive composition (Lx-110, manufactured by Nippon Zeon Co., Ltd.) 50 parts to 100 parts, the same manner as in Reference Example 3 Then, a releasable pressure-sensitive recording paper was prepared, and this was designated as Example 12. Table 1 shows the results of evaluation of the obtained releasable pressure-sensitive recording paper by a peel strength test, a printability test, and a blocking test.
[Example 13]

The same as Reference Example 3 except that 50 parts of the styrene-butadiene copolymer adhesive (Lx-110, manufactured by Nippon Zeon Co., Ltd.) in the coating liquid 2 of the pressure-sensitive adhesive composition of Reference Example 3 were changed to 150 parts. Thus, a releasable pressure-sensitive recording paper was prepared, and this was designated as Example 13. Table 1 shows the results of evaluation of the obtained releasable pressure-sensitive recording paper by a peel strength test, a printability test, and a blocking test.

[Comparative Example 1]
The synthetic silica of the coating solution 1 of the pressure-sensitive adhesive composition of Reference Example 1 was changed from Mizukasil P-78A to Aerosil 50 (specific surface area 50 m ² / g, oil absorption 90 g / 100 ml, manufactured by Nippon Aerosil Co., Ltd.). A releasable pressure-sensitive adhesive recording paper was prepared in the same manner as in Reference Example 1 except that the pressure-sensitive adhesive composition coating solution 4 was used, and this was designated as Comparative Example 1. Table 1 shows the results of evaluation of the obtained releasable pressure-sensitive recording paper by a peel strength test, a printability test, and a blocking test.

[Comparative Example 2]
Except for changing the styrene-butadiene copolymer adhesive 50 parts to 230 parts by coating liquid 2 of the pressure-sensitive adhesive composition of Reference Example 3, to create a refastenable bonding recording paper in the same manner as in Reference Example 3 This was designated as Comparative Example 2 . Table 1 shows the results of evaluation of the obtained releasable pressure-sensitive recording paper by a peel strength test, a printability test, and a blocking test.

[Comparative Example 3]
A releasable pressure-sensitive recording sheet was prepared in the same manner as in Reference Example 1 except that 50 parts of the natural rubber adhesive was changed to 30 parts with the coating solution 1 of the pressure-sensitive adhesive composition of Reference Example 1. Was designated as Comparative Example 3. Table 2 shows the results of evaluation of the obtained releasable pressure-sensitive recording paper by a peel strength test, a printability test, and a blocking test.

[Comparative Example 4]
A releasable pressure-sensitive recording sheet was prepared in the same manner as in Reference Example 1 except that 50 parts of the natural rubber adhesive was changed to 230 parts with the coating solution 1 of the pressure-sensitive adhesive composition of Reference Example 1. Was referred to as Comparative Example 4. Table 2 shows the results of evaluation of the obtained releasable pressure-sensitive recording paper by a peel strength test, a printability test, and a blocking test.

[Comparative Example 5]
Except for changing the styrene-butadiene copolymer adhesive 50 parts 30 parts of coating solution 2 of the pressure-sensitive adhesive composition of Reference Example 3, to create a refastenable bonding recording paper in the same manner as in Reference Example 3 This was designated as Comparative Example 5. Table 2 shows the results of evaluation of the obtained releasable pressure-sensitive recording paper by a peel strength test, a printability test, and a blocking test.

Various physical properties of the releasable pressure-sensitive recording paper obtained in the above Examples and Comparative Examples were evaluated according to the following test methods.
(1) Contact angle evaluation The contact angle of the pressure-sensitive adhesive layer surface of the obtained sample with respect to the silicone oil was determined according to ASTM D5725 by applying a silicone oil with a capacity of 3 μL to the adhesive layer in an atmosphere of 23 ° C. and 50% RH. The measurement was made 10 seconds after the dropping. The contact angle measuring apparatus used was FIBRO DAT 1100, a dynamic contact angle absorption tester manufactured by FIBRO system ab.
(2) Adhesive strength The sample was cut into a width of 100 mm and a length of 100 mm, and the coated surfaces of the sample pressure-sensitive adhesive composition were overlapped with each other using a dry sealer (Pressle Econo: manufactured by Toppan Foams Co., Ltd.). Pressure bonding was performed. Next, the widthwise central portion of this sample was cut to a width of 25 mm, and peeled off at a speed of 300 m / min with a strograph M-1 type (manufactured by Toyo Seiki Seisakusho) at 23 ° C. and 50% RH. It peels with intensity | strength, the resistance value is averaged, peel strength g / 25mm is calculated | required, and it evaluates as adhesive strength. A: 100 to 150 g / 25 mm, O: 50 to less than 100 g / 25 mm, Δ: 20 to less than 50 g / 25 mm, X: 0 to less than 20 g / 25 mm, A and O indicate peel strength at a practical level, Δ And x indicate levels that cannot be practically used.
(3) Adhesive strength after application of silicone oil 0.4 g / m of silicone oil in a packaged state using a RI-3 type printability tester (manufactured by Meisei) on the pressure-sensitive adhesive composition coated surface of the sample. ^{After two} coatings, the peel (T-type peel) strength is measured as described in (2) above, and the evaluation is performed based on the retention rate using the (2) peel strength of the same sample as the denominator. A: Peel strength is 85 to 100%, O: Peel strength is kept less than 60 to 85%, A: Peel strength is kept less than 45 to 60%, X: Peel strength is less than 45%.
(4) Blocking resistance Blocking aptitude test: A sample coated on both sides of a pressure-sensitive adhesive composition is superposed and left under a load of 500 g / cm ^{2 in} an environment of 23 ° C. and 50% RH, and after 24 hours. It peeled off by hand and evaluated. (Double-circle): Blocking has not generate | occur | produced at all, (circle): Blocking has hardly generate | occur | produced, (triangle | delta): Blocking has generate | occur | produced a little, X: It has blocked completely.
(5) Printing resistance Using a RI-3 type printing aptitude tester (manufactured by Meisei Seisakusho), the printing durability of the coated surface of the pressure-sensitive adhesive composition of the sample was evaluated. Ink was 0.4 ml of process ink (Toyo Ink Manufacturing Co., Ltd., PRINTING INK, black ink, SMX, TV-25), printing speed: 60 rpm, 4 times printing. Evaluation was made by visual sensation, and “A”, “O”, “Δ”, and “X” were given in the order of no coating layer peeling by ink and no paper peeling.
(6) Comprehensive evaluation Comprehensive evaluation as a releasable pressure-sensitive recording paper was performed.
◎: Excellent as a releasable pressure-sensitive recording paper, ○: Excellent as a releasable pressure-sensitive recording paper, △: There is some problem as a re-peelable pressure-sensitive recording paper, and there is anxiety in practical use. : There is a problem as a re-peelable pressure-sensitive recording paper and it cannot be used in practice.

  The test was conducted according to the above method, and the evaluation results are shown in Table 1 below.

As can be seen from the results in Table 1, in the case of Reference Examples 1 to 5 in which the contact angle 10 seconds after dropping the silicone oil on the pressure-sensitive adhesive layer surface was 60 ° or less, the electrostatic recording method (electrophotographic method) When printed with a heat roll fixing printer, the decrease in adhesive strength after application of silicone oil, which is a release agent used to prevent toner transfer to the heat roll, is small. It can be seen that a releasable pressure-sensitive recording paper satisfying the peelability can be obtained. In contrast, in the case of Comparative Example 1 where the contact angle is 75 °, which is greater than 60 °, and Comparative Example 2 where the contact angle is 63 °, a significant decrease in the adhesive strength after silicone oil application is observed.

As can be seen from Table 2, in the case of Reference Examples 1 to 13, when the amount of the adhesive is 50 to 200 parts by mass with respect to 100 parts by mass of the fine particle filler, whether it is a natural rubber adhesive or a synthetic adhesive. Is excellent in blocking resistance and printing resistance, but in the case of Comparative Example 3 and Comparative Example 5 in which the amount of adhesive is less than 50 parts by mass, the printing resistance is insufficient. In the case of Comparative Example 4 having 230 parts by mass greater than 200 parts by mass, the blocking resistance is insufficient, and cannot be practically used as a releasable pressure-sensitive recording sheet. It can be seen that it is important that the adhesive amount is 50 to 200 parts by mass with respect to 100 parts by mass of the fine particle filler.

Claims (2)

In pressure-releasable pressure-sensitive recording paper, which does not exhibit tackiness and adhesion at room temperature and pressure, exhibits adhesion when pressed, and has a pressure-sensitive adhesive layer that can be peeled off after pressure bonding. The adhesive layer is a pressure-sensitive adhesive composition comprising an adhesive and a fine particle filler, and the contact angle (ASTM D 5725) after dropping of the silicone oil on the surface of the pressure-sensitive adhesive layer (ASTM D 5725) is 60 ° or less, The fine particle filler is an inorganic pigment having a specific surface area of 150 to 550 m ² / g and an oil absorption of 80 to 400 mL / 100 g, and the adhesive is selected from a natural rubber adhesive or a synthetic adhesive, and the natural rubber adhesive There is a resin obtained by 25% graft polymerization of methyl methacrylate, the synthetic adhesive is a styrene - Ri butadiene copolymer der, the adhesive to the particulate filler 100 parts by weight of 100 to 180 parts by weight Peelable crimp recording paper characterized in that it comprises. The releasable pressure-sensitive recording sheet according to claim 1, wherein the adhesive contains 100 to 170 parts by mass with respect to 100 parts by mass of the fine particle filler.