JPH04173294A - Thermal stencil paper - Google Patents

Abstract

PURPOSE:To obtain thermal stencil paper excellent in both of perforating plate making properties and printing durability by employing an adhesive based on a polymer of a specific long chain alkyl (meth)acrylate whose alkyl group has a specific number of carbon atoms. CONSTITUTION:Thermal stencil paper is formed by laminating a polyester film and a porous support using an adhesive. The adhesive is based on a polymer of long chain alkyl (meth)acrylate having a 15-22C alkyl group. Since the 15-22C long chain alkyl polymer is excellent in thermal softening properties and does not obstruct thermal perforating properties and has good ink resistance, the stencil paper excellent in printing durability can be obtained by the use of this adhesive. In addition, it is estimated that the aforementioned polymer has action reducing and preventing the tackiness of the thermal perforating molten substance of the film with respect to the thermal fusion phenomenon due to a thermal head and it is unnecessary to provide a fusion preventing layer to the surface of the film or the fusion preventing layer may be provided in an extremely slight amount of 0.002-0.01g/m<2>.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a heat-sensitive stencil paper having a structure in which a polyester film and a porous support such as porous thin paper or a mesh-like sheet are bonded together using an adhesive. .

[Prior Art] Conventionally used heat-sensitive stencil paper has a structure in which a heat-melting shrinkable resin film is bonded to a porous support that is permeable to stencil printing ink, which does not melt and shrink at the temperature at which the film melts and shrinks. A coating is provided on the surface of the film to prevent fusion with the original or the heating element.

That is, the components of the heat-sensitive stencil paper are the two members, the heat-melt shrinkable film and the porous support, and it is essential that these are laminated and bonded tightly together.

The reason for this is that the heat-melt shrinkable film used is extremely thin with a thickness of 10 μm or less, so it is not only weak and inconvenient to handle, but also deforms and distorts during plate-making heating, or the perforated parts may fall off. This is because there is no use in doing so.

Therefore, it is necessary to adopt a laminated structure of a film and a porous support, and since it is a laminated structure, an adhesive is essential, and the selection of adhesive is an important factor that influences the quality of heat-sensitive stencil paper. becomes.

Therefore, many patent applications have been filed regarding the selection of adhesives.

That is, a method of applying 1.5 to 7 m2 of acrylic resin (Japanese Patent Publication No. 1987-1.1.87), and a method of applying 2 to 10 g/I of an adhesive whose main component is vinyl acetate resin.
Method of applying N2 (Japanese Patent Publication No. 47-1.1.88)
, a method in which vinyl acetate resin is dissolved in a mixed solvent of methanol and other alcoholic solvents (Japanese Patent Publication No. 47-17
338), 0.1 to 5 g of saturated polyester resin
/m2 method (Japanese Unexamined Patent Publication No. 1824.96/1983), 05 to 2 g of adhesive whose main component is acrylic resin
/m2 coating method (Japanese Patent Publication No. 51/1988-38004), method using vinyl acetate resin added with rosin resin (Japanese Patent Application Laid-open No. 59-1-6788), coating film with vinyl acetate, acrylic A method in which a type adhesive is applied and dried, and porous paper impregnated with a water-dispersed vinyl acetate resin is layered on this surface in an undried state, dried, and bonded (Japanese Patent Application Laid-Open No. 16795-1982). There is a method using methoxymethylated polyamide (Japanese Unexamined Patent Publication No. 59-1.15899). When these vinyl acetate resins, acrylic resins, polyester resins, etc. are used as adhesives, if the solid resin content is not more than 1 g 7 m 2 at the time of bonding, the film will float or wrinkle. In addition, these resin adhesives have poor water resistance, so they soften, swell, and dissolve in the printing ink. If the ink penetrates into the fibers and the amount of adhesive is small, it will peel off easily, so at least the amount of adhesive is 1. ．．
It is necessary to increase the area to 5g, 7m2 or more, but this will reduce the print clarity.

01-5g of adhesive whose main component is vinyl chloride polymer
/m2 coating method (JP-A-59-215894), method using chlorinated propylene resin (JP-A-Sho [12
1,589) has the disadvantage that the chlorinated resin releases harmful chlorine into the thermal head during plate making. 03-2.5g of isonanate prevolimer on the film surface
A method of coating 7 m2 and pressing at a pressure of 2 kg/m2 or more (Japanese Unexamined Patent Publication No. 6595), NGO1011 of diisocyanate-1 and polyether diol with an average molecular weight of 400 to 2000 is 1 .5-2
．． The method of using an adhesive mainly composed of a reacted prepolymer with a 0 equivalent ratio and having a flow start temperature of 150 to 260°C after curing (Japanese Patent Application Laid-open No. 181374) has good ink resistance. Although it is possible to change to a type with higher printing durability even in small quantities, it is difficult to control the pot life of the adhesive solution and adjust the humidity, which tends to cause uneven curing. Furthermore, although this method specifies that the urethane resin used is one that easily heat softens and has a low degree of inhibiting perforation, there is a large difference in adhesive strength depending on the amount of application, and in reality, a considerable amount of urethane resin is used. Adhesives are required, and as a result, perforability is inevitably inhibited. After all, thermosetting urethane resins, Epoquine resins, and melamine resins have excellent adhesive strength and ink resistance, but their perforation properties are significantly reduced and they cannot be used.

In contrast to these technologies, a two-component reactive adhesive consisting of an active hydrogen-containing resin and an isocyanate can be used as an adhesive that provides strong adhesion in a small amount and has excellent ink resistance and perforation properties, but it is difficult to handle. .

Ionizing radiation-curable and ultraviolet-curable adhesives have been proposed as other reactive adhesives, but these not only require special equipment but also tend to leave uncured material behind, so they cannot be used with a thermal head during plate-making. This causes fusion.

Second thing: With conventional technology, printing durability cannot be achieved without using a large amount of adhesive with resins that do not contain harmful substances such as chlorine and are relatively heat-softening. If an excessive amount of adhesive is used, perforation plate-making performance will be impaired. In addition, reactive adhesives have strict restrictions on reaction conditions and only have large variations in performance, and only two-component adhesives with Isonane-1 and additives, which cure slightly at room temperature and have strong affinity with the support, are stable and have good performance. Although I'm tired, I can't escape the work constraints of bot life.

= 6- Furthermore, in both non-reactive and reactive systems, a treatment layer must be newly provided on the surface of the bonded film to prevent fusion with the thermal head. That is, when making a plate using a thermal head, the film that is in contact with the thermal head is melted by the heat of the thermal head and perforated, causing a phenomenon in which the molten film at the perforated portion sticks to the thermal head. Therefore, it is unavoidable to some extent to apply an anti-fusion layer. However, the adhesive used is one with a heat softening temperature lower than the melting point of the film so as not to inhibit the thermal perforation of the film, and since the adhesive is integrated with the film and naturally melts at the perforations during plate making. , weakening the adhesion between the film and the porous support. Furthermore, the tackiness of the molten adhesive greatly influences the phenomenon of fusion to the thermal head, but this has not been considered at all in the past.

[Problems to be Solved by the Invention] The present invention uses a non-reactive adhesive that is free from reaction conditions and operational constraints, and uses a small amount of adhesive to firmly bond a polyester film and a porous support. In addition, it is necessary to use heat-sensitive stencil paper that has excellent perforation plate-making properties and printing resistance, and to provide a coating layer on the surface of the bonded polyester film to prevent fusion with the thermal head. The purpose is to scale heat-sensitive stencil paper, which does not require a large amount of paper, or requires a small amount.

[Means for Solving the Problems] The present invention provides a heat-sensitive stencil paper formed by bonding a polyester film and a porous support using an adhesive.
The present invention relates to a heat-sensitive stencil paper, characterized in that the adhesive is mainly composed of a polymer of long-chain alkyl (meth)acrylate having an alkyl group having 15 to 22 carbon atoms.

[Function and Examples] The present invention mainly uses a conventional alkyl acrylate adhesive having an alkyl side chain having 2 to 8 carbon atoms,
Moving away from the perspective of adjusting the hardness and softness of the film quality by adjusting the alkyl chain length, we conducted intensive research into a completely new hydrophobic adhesive, which is a polymer of long-chain alkyl (meth)acrylate with 15 to 22 carbon atoms. It was discovered that a polymer in which alkyl chains exist in a pendant form as side chains is effective as an adhesive for the heat-sensitive stencil paper, and the present invention was achieved based on this finding.

The features of the present invention are as follows.

■In the conventional technology, (1) increasing the amount of coating (Li
) Use of thermosetting resin, (fit) Use of chlorine-containing resin, (iv) Use of specific urethane resin, (v) Use of two-component curing resin, (vi) Curing type resin using special equipment. Use a one-component, non-reactive adhesive.

■We discovered that the tackiness of the adhesive when softened by heat affects its fusion to the thermal head, and from this point of view, we reduced the fusion properties of the film by using a non-adhesive thermosoftening resin as the adhesive. .

In other words, during plate making, the film is perforated by heating with a thermal head, but at that time the adhesive obstructs the perforation, and the adhesive film must also be perforated in this area, so the adhesive has a melting point lower than the film's melting point. Thermal softening properties at certain temperatures are required. In the past, various efforts were made to satisfy the mutually contradictory factors of heat softening and printing durability, which is the original function of thermal stencil paper, and adhesion and fusing of the film to the thermal head were two different things. It was thought that.

By the way, conventional techniques and commonly used acrylic adhesives include ethyl acrylate, butyl acrylate,
Mainly composed of 2-ethylhexyl acrylate, and methacrylic esters (methyl, ethyl, butyl, 2-ethylhexyl).
ethylhexyl) and styrene, acrylonitrile,
A copolymer with vinyl acetate further improves affinity with the adherend (
= 1, so some polarity h (is introduced).

Furthermore, when imparting thermosetting crosslinking properties, N-methylolacrylamide, glycidyl acrylate, etc. are used as copolymerization monomers.

- ]〇 - In all of these conventional adhesives, the alkyl carbon number is 2 to 8. Alkyl carbon numbers up to 4 reduce the crow transition temperature (Tg) of the polymer in proportion to the chain length, so in special cases, alkyls with carbon numbers exceeding 8 may be used in adhesives. Even in that case, the number of carbon atoms was limited to 14 or less.

The polymer of long-chain alkyl acrylate or methacrylate-1, which is a product of the adhesive of the present invention, is a mixture of acrylic acid or methacrylic acid and cetyl alcohol, pentadecanol, stearyl alcohol, behenyl alcohol, etc. having 15 to 22 carbon atoms. It is polymerized using a conventional method using an ester with a higher alcohol as a monomer. The monomers may be used alone or in combination of two or more. At this time, in addition to the above monomers, other monomers such as acrylonitrile and butyl acrylate may be added and copolymerized, or polar groups may be introduced, such as acrylic acid, methacrylic acid, itaconic acid, etc. in the case of carboxyl groups. , maleic acid, hydrogine acrylate-1 or methacrylate-1 for the hydroxyl group, and aminoacrylate or aminomethacrylate for the amino group may be copolymerized. In these cases, it is preferable that the amount of the monomer used in the copolymerization is such that the content of long-chain alkyl acrylate in the copolymer does not become less than 60 mol%. The long chain alkyls of these acrylates or methacrylates are pendant as side chains. The reason why long-chain alkyl polymers having 15 to 22 carbon atoms are effective as adhesives for heat-sensitive stencil paper is thought to be due to the following points. In other words, when the number of carbon atoms in the alkyl group is 8 or more, the polymer becomes flexible and loses its plasticity due to the side chain effect, but when the number of carbon atoms is 15 or more, the alkyl moiety concentration is high and it exhibits hydrophobic and water repellent properties, and the polymer becomes less flexible due to the side chain effect. It has a protective effect, which improves chemical resistance and also improves heat resistance, reaching temperatures of 50 to 60°C.
This is because it becomes non-flowing and non-deformable.

Regarding the glass transition point (Tg) of a polymer, =
12 - C8 2-ethylhexyl methacrylate one 2
Lauryl methacrylate-1/-65° at 0°CXC12
C, but cetyl methacrylate of 016 is 15℃,
Stearyl methacrylate No. 018 shows a temperature of 38°C.

Furthermore, these polymers exhibit non-adhesiveness and peelability in a thermally softened state.

Therefore, the long-chain alkyl polymer having 15 to 22 carbon atoms has good heat softening properties, does not impede heat perforation, and has good ink resistance, so it can be used as an adhesive to improve printing durability. I can scale the stencil paper you gave me.

In addition, it is presumed that the polymer has the effect of reducing or preventing the adhesion of the thermally punched melt of the film with respect to the phenomenon of thermal fusion of the film with the thermal head, and therefore it is necessary to provide an anti-fusion layer on the surface of the film. No, or 0.002
~O,01g7m2, which is very small.

The adhesive of the present invention may contain 13- tack modifiers and other additives such as rosin, ester gum, terpene resin, coumaron resin, etc., in an amount not exceeding 30% by weight of the total composition. I can do it.

The polyester film used in the present invention is a stretched film having a thickness of 5 μm or less, preferably 10 to 30 μm. If the thickness exceeds the above range, the perforation performance due to the thermal energy of the thermal head will be poor and it will not be possible to produce a stencil that is faithful to the original. If the thickness reaches the end of the range K, the strength will become too small, which is not preferable. As the polyester film, a double-stretched film is usually used, and it is preferable that the stretching ratio is 150 to 250% in both the longitudinal and transverse directions.

Porous supports include natural fibers such as mitsumata, Manila hemp, and jute, semi-synthetic fibers such as rayon, and synthetic fibers such as polyester, vinylon, nylon, and polypropylene, either singly or in a mixture of two or more. Basis weight 5
~1.5 g 7 m2 of porous thin paper, 50 to 200 mesh screen gauze made of synthetic fiber or a mixture of two or more synthetic fibers are preferably used.

The production of heat-sensitive stencil paper in the present invention is carried out as follows. That is, an adhesive solution in which the acrylate or methacrylate polymer of the long-chain alkyl alcohol and other ingredients as necessary are dissolved in a suitable organic solvent,
Solid content on polyester film 02-1.5g 7
It is coated so that it has a thickness of m2, and is then bonded to a perforated support using a wet laminate method. In order to provide an anti-fusing layer on the film surface of the obtained stencil paper, if necessary,
Coating solution for anti-adhesion layer is applied and dried.

The present invention will be explained below with reference to Examples.

Example 1 Stretched polyester film with a thickness of 2μ and a weight of 1,]
A 7 m2 piece of book paper was applied to the film with the following adhesive and bonded together using the Uenotralamination method.

Adhesive coating liquid components Polymer mainly based on stearyl methacrylate-1 (solid content 18% (weight, same as below), manufactured by Ichisha Yushi Kogyo Co., Ltd., Pearoyl IIT) 30% ethyl acetate-toluene mixture (volume ratio) 50:50) 60 The following liquid was used as the coating liquid for the anti-fusing layer provided on the film surface of the bonded base papers.

Ingredients Parts by weight Acrylic fluorine block polymer (solid content 30%, Modiper P-200 manufactured by Roki Yushi Kogyo ■) Ethyl 5-acetate-toluene, isopropyl alcohol mixture (volume ratio 40:20:40)
Comparative Example 100 A stencil paper was produced in the same manner as in Example except that the adhesive coating liquid was replaced with a methanol solution of polyvinyl acetate (solid content 15%).

Comparative Example 2 An adhesive coating solution was mixed with a toluene-methyl ethyl ketone (volume ratio 70:30) solution (solid content I) of a copolyester consisting of terephthalic acid, sebacic acid and ethylene glycol.
A stencil paper was produced in the same manner as in Example 1 except that the concentration was changed to 0%).

Comparative Example 3 An ethyl acetate-toluene solution (solid content 50%) of a moisture-curable terminal isocyanate prepolymer was applied as an adhesive to the film surface at a rate of 4 g/m 2 and bonded.

The base paper was plate-printed using a Gestettner CD550 (1.6 dots h/mm thermal head plate-making printing machine), and a chart based on the facsimile test chart 1 of the Institute of Image Electronics Engineers of Japan was used as the manuscript.

Performance evaluation of the adhesive was performed based on trailing resistance, plate-making printability, and printing durability. Table 1 summarizes the adhesive, the coating amount of the anti-fusion layer, and the evaluation of the adhesive.

1 18 - [Effects of the Invention] Hereinafter, the adhesive according to the present invention has good workability as a one-liquid adhesive, and a heat-sensitive stencil paper obtained by laminating a polyester film and a porous support using it. is plate-making printability,
It has poor printing durability.

Patent applicant: Asia Base Paper Co., Ltd.

Claims (1)

[Claims] 1. In a heat-sensitive stencil paper formed by bonding a polyester film and a porous support using an adhesive, the adhesive is a polymerized long-chain alkyl (meth)acrylate with an alkyl group having 15 to 22 carbon atoms. Heat-sensitive stencil paper characterized by being mainly composed of