KR960008082B1 - Ink compounds for thermal transfer - Google Patents

Abstract

The ink composition includes of 60-95 wt% acrylpolymer whose number average molecular weight is 100-500 and whose molecular weight distribution is 1.00-1.20, organic solvent and pigment. The acrylpolymer is a homopolymer of methylmetacrylate, ethylmetacrylate, methylacrylate or ethylacrylate, or copolymer of methylmetacrylate, normalcrylate or allymetacrylate. The ink can be used on a variety of copying materials such as paper, polyester, acryl, polypropylene, and nylon polyvinylene chloride.

Description

Thermal Transfer Ink Compositions

The present invention relates to a heat transfer ink composition, and more particularly, to a heat transfer ink composition containing an acrylic resin as a main component.

Recently, as office automation devices and document writers are widely used, there is an increasing demand for new printing means that generate less noise and have a faster printing speed. The thermal transfer recording device applies thermal ink on a support and is heated to transfer the ink to a recording medium to form a recording. The noise generation is less than that of a dot printing machine, the printing speed is faster, and it is smaller than that of a laser printing machine. It is suitably used as a printing means for word processors or portable personal computers.

The following types are known as conventional thermal transfer ink compositions and thermal transfer recording media using the same. Japanese Patent Laid-Open No. 61-228,993 discloses a thermal transfer recording medium in which the thermal transfer recording medium is coated with an ink composition consisting of paraffin wax, ethylene-ethylene acetate copolymer, and carbon black on a base film. Paraffin wax is melted by controlled heat in the apparatus, and carbon black dissolved in paraffin wax is transferred to paper and printed.

However, such a technique is difficult to transfer to a variety of transfer targets because the ink composition contains wax as a main component, lacks durability after printing, difficult to clean after coating, and is difficult to produce in parallel with other items. Since there is no heat-resistant active layer on the opposite side of the ink layer, there is a problem in that the back side of the film is worn or caught by the protrusion of the heating element of the thermal transfer recording apparatus while driving, and printing is stopped.

Japanese Patent Application Laid-Open No. 57-129,789 discloses an ink composition consisting of cabana wax, paraffin wax, wax oxide, waserine and carbon black on one side of a base film, and on the opposite side, which is present in solid or semisolid form at room temperature. A thermal transfer recording medium is disclosed in which a resin layer containing an activator or organic salts is provided to improve the slidability of a thermal recording medium. However, this invention also has the same problem as in the invention of Japanese Patent Laid-Open No. 61-228,993 because the heat transfer ink composition contains wax as a main component.

Japanese Patent Laid-Open No. 60-97888 discloses a thermal recording medium in which a protective film is formed on an ink layer to protect the ink layer from contamination. However, this thermal recording medium also uses a wax as a main component since the thermal ink composition is composed of paraffin wax, ester wax polyethylene wax and carbon black.

Therefore, such a prior art based on wax has the same problems as the two prior arts described above.

Japanese Patent Application Laid-Open No. 63-11381 uses an ink composition composed of ethylene vinyl acetate copolymer, carbon black, and toluene, and prior to applying the ink on a support, an intermediate of a wax component is set on the support to heat the ink. Techniques for facilitating thermal transfer of layers are disclosed.

However, in this case, when the intermediate of the wax component is dissolved, the ink layer is dissolved into the wax layer, and since the ethylene-vinyl acetate copolymer is used as the main component as the ink composition, the temperature range for melt transfer is wide, making it difficult to form a clear factor. There is this.

The present invention has been made in order to solve the problems of the prior art as described above, firstly, the object of the present invention is to transfer various kinds of transfer materials, for example paper, polyester, acrylic, poly Fourthly, propylene, nylon polyvinylene chloride, and the like are well transferred, and secondly, excellent durability after printing, and thirdly, a single molecular weight resin is melt-transferred in a narrow temperature range, and fourth, resin is formed. It is possible to produce in general gravure coating machine by dissolving in a solvent, and fifthly, it is easy to clean after coating operation, so that it can be produced in parallel with other items at the same expectation, so that it is possible to improve the operation rate of expectation. To provide.

In order to achieve the above object of the present invention, the present invention is an acrylic polymer having a number average molecular weight of 100 to 500 and a ratio (molecular weight distribution) of the number average molecular weight and the weight average molecular weight of 1.00 to 1.20, and an organic solvent; It provides a thermal transfer ink composition made of a pigment.

The number average molecular weight and the weight average molecular weight have the following relationship with respect to the molecular weight distribution of the weight body.

When the above molecular weight distribution has a value of 1, it means that the molecular weights of all the molecules constituting the weight have the same value. Therefore, in order to obtain clear transfer, which is the object of the present invention, the molecular weight distribution of the thermal transfer ink is 1; The closer you are, the better.

The molecular weight distribution of the acrylic polymer suitable for this invention is 1.00-1.20.

When the molecular weight distribution of the acrylic polymer is 1.20 or more, a problem arises that the molecular weight distribution of the polymer is large so that the thermal transfer ink composition is melt-transferred at a wide range of temperatures, thereby making it difficult to form a clear factor.

Moreover, as for the molecular weight of the acrylic polymer in the composition suitable for this invention, 100-500 are preferable at a number average molecular weight.

If the number average molecular weight is 100 or less, it is difficult to form a film on the base film, there is a problem that the particles fall off during coating.

And, if the number average molecular weight is 500 or more, there is a problem that the melting point of the ink composition is increased, the chemical formation rate is low and the printing speed is lowered.

As the acrylic polymer having a molecular weight of 100 to 500 and a molecular weight distribution of 1.00 to 1.20 suitable for the present invention, a homopolymer of methacrylate, ethyl methacrylate, methyl acrylate or ethyl acrylate or normal butyl methacrylate, Preference is given to using copolymers of normal butyl acrylate, allyl methacrylate or allyl acrylate. These acrylic polymers can be produced by a known functional group-trasper polymeryzation method.

The acrylic polymer having the above properties is dissolved in an organic solvent consisting of methylene chloride, toluene and ethyl acetate together with a dye such as carbon black to constitute the thermal ink ink composition of the present invention.

As for the content of the acrylic polymer in this thermal transfer ink composition, 60 to 95 weight% is preferable with respect to solid content of an ink composition.

When the content of the acrylic polymer is 60% by weight or less, the ink composition of the acrylic polymer component is melted together when melting the wax release layer provided between the support and the ink layer so as to facilitate the transfer of ink when applied to the thermal transfer recording medium. If mixed with the wax layer occurs, there is a problem that the transfer is poor.

In addition, at 95 wt% or more, there is a problem in that the amount of the dye and carbon black present in the ink composition is small and the post-transfer factor concentration becomes weak.

Next, a preferred embodiment of the present invention is presented.

However, these examples are provided only for easier understanding of the present invention, and the present invention is not limited only to the following examples.

Example 1

100 parts by weight of methyl methacrylate homopolymer having a molecular weight of 300 and a molecular weight distribution of 1.00,

Carbon black 25 parts by weight

50 parts by weight of methylene chloride

30 parts by weight of ethyl acetate

The composition having the composition described above was stirred with a homo mixer for 2 hours to prepare a thermal transfer ink composition.

The ink composition was applied on a wax-coated surface of a 3.5-micron-thick polyethylene terephthal film coated with a non-silicone compound, Trl-30, a non-silicone compound, Trl-30, which was coated on the lower surface and 0.3 μm of paraffin wax on the other side. The thermal transfer recording medium was prepared by coating and drying the layer to a thickness of 3.5 탆.

Example 2

As the acrylic polymer of Example 1, a recording medium was prepared in the same manner as in Example 1 except that an ethyl acrylate homopolymer having a number average molecular weight of 300 and a molecular weight distribution of 1.03 was used.

Example 3

The acrylic polymer of Example 1 was treated in the same manner as in Example 1 except that a methyl methacryl-normal butyl methacrylate-allyl methacrylate copolymer having a number average molecular weight of 300 and a molecular weight distribution of 1.07 was used. Four recording media were prepared.

Comparative Example 1

Cabana wax 40 parts by weight

Caraffin wax 40 parts by weight

20 parts by weight of ethyl-vinylacetate copolymer

Carbon black 25 parts by weight

A thermal transfer recording medium was manufactured in the same manner as in Example 1 except that the composition having the above composition was used as the thermal ink composition.

Comparative Example 2

30 parts by weight of ester wax

40 parts by weight of polyethylene wax

30 parts by weight of ethylene-vinylacetate copolymer

Carbon black 25 parts by weight

A thermal transfer recording medium was manufactured in the same manner as in Example 1 except that the composition having the above composition was used as the thermal ink composition.

Comparative Example 3

A thermal transfer recording medium was prepared in the same manner as in Example 1 except that the methyl methacrylate homopolymer having a number average molecular weight of 100 and a distribution of 3.5 was used as the acrylic polymer of Example 1.

The characteristics of the thermal transfer recording medium manufactured according to the above-described Examples and Comparative Examples were measured by the following method and are shown in Table 1 below.

1. Melting temperature range: Using a model DSC-4 instrument from Perkin Elmer, USA, the temperature was measured at a temperature of 20 ° C./min in a nitrogen stream.

2. Transferability: After transferring at 38cps printing factor and 0.7mJ / dot printing condition using a Daewoo Electronics word processor (model name: Lemo III, CWP-3080), Macbeth transmission photometer was used for optical reflection density. Measured. As the object to be transferred, paper coated or laminated with polyester, nylon, polypropylene, and acrylic resin and plain paper having a surface smoothness of 28 seconds were used.

3. Durability of print: After processing at a printing speed of 38 cps and printing heat of 0.7mJ / dot in Daewoo Electronics Co., Ltd. word processor (model name: Lemo III, CWP-3080), 300g of plain paper with 28 seconds of smoothness is stacked on the transferred paper. After 100 times of friction, the optical reflection density was measured with a MacBus transmission photometer and compared with the optical reflection density immediately after the transfer.

4. Gravure Coating Machine Applicability: The appearance was observed after coating the ink composition on the transfer support with 200 mesh gravure using a roller.

5. Cleanability: 5 g of the ink composition was mixed with 100 ml of an organic solvent composed of methyl ethyl ketone, ethyl acetate or toluene, and then dissolved. Cleanability is good when complete dissolution is achieved.

As can be seen from the results of Table 1, the ink composition for thermal transfer of the present invention has good transferability, and various kinds of coatings such as paper coated or laminated with a synthetic resin such as polyester, nylon, polypropylene, or acrylic, in addition to ordinary paper. Has the scope of sate.

In addition, since the melting temperature variation of the thermal transfer ink composition of the present invention has a temperature deviation of 2 ° C., which is very small compared to 7 to 10 ° C. in the case of the conventional wax type thermal transfer ink composition, the formation of a very clear factor is achieved compared to the conventional ink composition. .

In addition, the thermal transfer ink composition of the present invention has an acrylic polymer as a main component, so that it is soluble in a general organic solvent, and gravure printing is possible, so that the thermal transfer recording medium is suitable for mass production.

In addition, since it has good solubility in organic solvents as described above, it is easy to clean during the manufacturing process of the thermal transfer recording medium, the time required to change the line is short, and the operation is easy to produce the thermal transfer recording medium of various items in one production line. This is possible.

Claims (5)

A heat transfer ink composition comprising an acrylic polymer having a number average molecular weight of 100 to 500 and a non-nine molecular weight distribution of the number average molecular weight and a weight average molecular weight of 1.00 to 1.20, an organic solvent, and a pigment. The heat transfer ink composition according to claim 1, wherein the content of the acrylic polymer is 60 to 95 wt% based on the total solids of the heat transfer ink composition. The ink composition of claim 1, wherein the acrylic polymer is a homopolymer of methyl methacrylate, ethyl methacrylate, methyl acrylate or ethyl acrylate. The ink composition of claim 1, wherein the acrylic polymer is a copolymer of methyl methacrylate, normal butyl methacrylate or allyl methacrylate. A thermal transfer recording medium comprising gravure printing of the thermal transfer ink composition of claim 1.