JPS6049599B2 - resin bonding layer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a bonding layer for bonding an ink layer to a film substrate.

BACKGROUND OF THE INVENTION Conventionally, ink oozing type reusable transfer materials are well known in the field of carbon paper and carbon ribbon.

Such a transfer material has a microporous skeletal resin structure that is not substantially transferred when an image forming pressure is applied, and contains an oil-based ink that can be transferred by the image forming pressure in the microporous structure. are doing. However, if the microporous resin structure is not firmly bonded to its base material, the microporous resin structure will break and crumble, resulting in speckled transfer onto the copy sheet, and the transfer material will no longer be uniform. cannot be used repeatedly to obtain a unique copy. Between a flexible substrate and a reusable microporous transfer layer according to U.S. Pat. No. 3,037,87. It is known to provide a resin bonding layer and to solvent-bond the microporous transfer layer to the resin bonding layer so that the transfer layer does not transfer during use. In this method, a volatile organic solvent is used as a solvent for the resin of the bonding layer, and dissolves the surface of the bonding layer to bond the bonding layer to the microporous resin structure of the ink layer, which is the transfer layer. , is formed by coating an ink layer made of a microporous resin. Further, according to U.S. Pat. No. 3,314,814, an ink-leaching microporous resin is produced from an aqueous solvent system using a material having a film-forming ability such as polyvinyl alcohol that is soluble in water or a mixture of water and alcohol. It is also known that ink layers can be produced.

Although aqueous compositions tend to be repelled by resin surfaces such as plastic films and resin-coated films and papers, adding an aliphatic alcohol solvent to the aqueous composition can improve the affinity of the aqueous composition for such resin surfaces. sex is improved. However, the affinity bond is not as strong as the soluble bond, and such transfer materials have poor fracture resistance required for repeated use. Attempts to overcome the aforementioned problems by using tie layers based on water-soluble binder materials such as polyvinyl alcohol or water-emulsifying binder materials such as polyvinyl acetate latex have not yet been successful. The resulting copying material is commercially unacceptable because the polyvinyl alcohol tie layer causes the flexible substrate, such as paper or plastic film, to curl or roll up. Also, the polyvinyl acetate bonding layer becomes insolubilized during drying and cannot form a soluble bond with the composition of the ink layer. These above-mentioned problems have been solved by a bond made of a mixture of a water-soluble resin binder material and a water-insoluble resin binder material in a specific ratio, according to US Pat. No. 3,904,803 issued on September 9, 2019. This is overcome by using layers. Although such a tie layer provides excellent results in itself, it requires a step of mixing the different binder materials described above in the required proportions.

Furthermore, because such a bonding layer contains both water-soluble and organic solvent-soluble resinous materials, the bonding layer is attacked by the solvent used to provide the ink layer thereon. Such solvent erosion can lead to uneven finishes on parts of the produced transfer sheet or transfer ribbon, unless the amount of solvent present in the applied ink layer and the degree of drying of the ink layer are not accurately controlled. Hail! Also, if the solvent invades the bonding layer excessively, the bonding layer becomes soft and stale. Moreover, the solvent remaining inside the bonding layer causes the transfer material to curl when it evaporates. As mentioned above, a microporous ink layer coated using an aqueous solvent, as disclosed in U.S. Pat. A bonding layer (disclosed in U.S. Pat. No. 3,904,803) consisting of a mixture of a water-soluble resin binder material and a water-insoluble resin binder material in a specific ratio that solves the problem has a strong bonding force, but The manufacturing process for transfer materials is complex and difficult to control.

It is therefore an object of the present invention to provide a bonding layer for firmly bonding a microporous resin ink layer, such as one applied using an aqueous solvent, to a flexible film substrate.

To achieve this objective, the resin bonding layer of the present invention provided between the microporous resin ink layer and the flexible film substrate, which is applied using an aqueous solvent, is a water-insoluble self-crosslinking layer. It is characterized by being made of acrylic resin.

The present invention provides that a resin bonding layer made of a water-insoluble self-crosslinking acrylic resin has a physical affinity, not a chemical affinity, for a microporous resin ink layer coated using an aqueous solvent. This is based on the knowledge that this provides a strong bonding force for the ink layer to the resin bonding layer (and therefore to the flexible film substrate). A preferred composition used in the manufacture of such resin bonding layers is Uker 152 (Uker 152).
It is formed from a binder material of a water-insoluble and water-dispersible self-crosslinking acrylic resin such as Carl 52 (manufactured by Union Carbide).

Eucre 152 is a 58% solids aqueous dispersion consisting of a water-insoluble self-crosslinking acrylic resin, which crosslinks upon drying to form an adhesive bond that is inert to water and organic solvents. form a layer. The resin bonding layer of the present invention is inert to volatile aqueous solvents used in applying the microporous resin ink layer.

Therefore, even if the amount of this aqueous solvent is large or the aqueous solvent is in contact with the resin bonding layer for a long time, the resin bonding layer will not become soft. As described above, the resin bonding layer of the present invention is not eroded by aqueous solvents, so by using this resin bonding layer, it is possible to easily obtain a pressure-sensitive transfer material with a uniform finish and no curling. can. If the transfer material is not manufactured in a continuous assembly line, the composition for forming the bonding layer may include, for example, particles of dennopone or an inert polymer that are uniformly dispersed in the bonding layer and spread over its surface. It is necessary to include some amount of particulate surface material such as clay, glass beads or other inert solid materials.

In this method, the surface material acts as a spacer so that the coated substrate 7 is wound into a roll before being sent to the subsequent step of applying the ink layer.
The back side of the substrate is prevented from adhering to the tie layer. The amount of surface material used is determined by its size and weight, but it is usually used in a proportion of about 1 to 15% based on the solid content of the composition for forming a bonding layer. The size of the surface material is such that its diameter is larger than the thickness of the dry bonding layer so that its particles are uniformly distributed in the bonding layer and are projected at least slightly above the surface of the bonding layer. preferable. The dry bonding layer according to the invention is about 0.635
~2.54μ(4). 25~1P01nt (0.000
025 to 0.0001 inch)), preferably about 1.2
7 to 1.91μ (a). 5 to 0.75P0int), so that the average particle size of the particulate surface materials used is at least about 10% larger than the predetermined thickness of the binder layer with which they are combined. be made larger. In addition, in the composition for forming a bonding layer according to the present invention, as a base material, for example, polyethylene terephthalate, polyethylene,
When using plastic films such as polypropylene, nylon, cellulose acetate, or other films with smooth surfaces, it is preferred to incorporate a small amount of a wetting agent into the composition.

As the wetting agent, it is generally preferable to use an anionic wetting agent in an amount of about 0.5 to 5% based on the solid content of the composition for forming a bonding layer. Next, the composition for forming a bonding layer used in the present invention will be explained with reference to Examples, but the present invention is not limited to these Examples. These components were uniformly mixed to prepare a coating composition having a solid content of about 26%. The composition had a thickness of 12.7 μm.
(stomach). 5mil) polypropylene film. 1.27μ thick (A). 5P0int(a).
A bonding layer of 05m11) was obtained. The acrylic resin, which is a resin component, becomes sticky by crosslinking and curing itself during drying. deer. However, because the dispersed starch particles protrude above the surface of the cured acrylic resin, when the coated film is rolled or rolled, the tackiness of the coating forming a bonding layer causes the film substrate to does not adhere substantially or to an undesirable extent to the uncoated backside of the substrate. In other words, the sticky resin portions in the tie layer adhere at the surfaces between each protruding starch particle, while the particles bond between the sticky portion of the coating and other sheets or smooth members. It acts as a spacer that can prevent the two from coming into contact and being fully adhered. However, when the finished transfer material is manufactured in a single assembly process, in other words, the bonding layer is dried,
If the ink layer composition is coated onto the tie layer quickly after curing, it is not necessary to include starch or other particulate surface materials in the tie layer forming composition.

Therefore, in this method, the composition in the above example is used for assembly line work. Modified to accommodate coating procedures. The undercoating composition (bonding layer forming composition) according to the present invention is an inert, curl-resistant and adhesive coating, and has excellent bonding strength to plastic film substrates. Ori,
Furthermore, it has excellent bonding strength to an ink-permeable resin ink layer applied using an aqueous solvent.

Preferred water-based compositions for use in the ink-wetting resin ink layer on the inert, adhesive bonding layer of the present invention are disclosed in U.S. Pat. No. 3,314,814; The composition is formed, inter alia, from a resinous binder material, water-soluble polyvinyl alcohol, an oil that is incompatible with the binder material, and a colorant.

Claims (1)

[Scope of Claims] 1 A resin bonding layer provided between a microporous resin ink layer coated using an aqueous solvent and a flexible film base material, comprising: (a) an adhesive layer; (b) Insoluble in the aqueous solvent; (c)
A resin bonding layer characterized in that it is a binder material of a cured water-insoluble self-crosslinking acrylic resin.