JPH0441798A - Method for producing a base material having a glossy coating and an apparatus for carrying out the same - Google Patents

Abstract

PURPOSE:To obtain the title substrate not requiring cooling for peeling, having extremely improved productivity and excellent luster by applying a specific coating agent to the surface of a printed substrate, heating and pressurizing and peeling the coated surface. CONSTITUTION:The surface of a platy substrate is printed, the surface of the printed substrate is covered with a coating agent containing an acrylic resin having 70-110 deg.C glass transition temperature and a phosphoric ester-based surfactant shown by the formula [R1 is alkyl (phenyl); (n) is 1-50; R2 is H, oxyethylene alkyl or oxyethylene alkylphenyl]. Then the coated surface is heated and pressurized by a heating and pressurizing means to form a luster face, the coated surface is released from the heating and pressurizing means without forcedly cooling the coated surface to give the objective substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing a substrate with a glossy coating and an apparatus for carrying out the same.

[Conventional technology]

Conventionally, in order to improve the gloss, abrasion resistance, water resistance, etc. of printed paperboard, the paperboard surface was coated with a coating agent using a roll coater or gravure coater, and then the coated surface was made glossy while being pressed. Surface processing methods are generally known. Such surface processing is generally performed using a pair of clamping belt type apparatus as shown in FIG. As shown in the figure, the device is equipped with a pair of opposing belt bodies 310 and 320, and the upper belt body 310 in the drawing includes a pair of rotary rolls 312 and 314 and an endless metal roll wound around these. belt body 320 at the bottom of the drawing.
Similarly to the belt body 310, a set of rotating rolls 322 is also provided.
．． 324 and an endless metal belt 327.

The clamping roll 312 at the tip of such an apparatus (on the right side of the drawing) is equipped with a heating mechanism such as steam (not shown), and is capable of heating and pressurizing the coating agent on the surface of paperboard or the like. These clamping rolls 312 and 322
After passing through the belts 317, 327 and the clamping rolls 314°324, a cooling mechanism (not shown) is provided between the belts 317, 327 and the clamping rolls 314°324.
The peelability between the roller 314 and the coating agent at the position is ensured.

In other words, the coating agent 410 applied to the surface of the workpiece 400 such as paper is given smoothness by passing through this device, and the printed paperboard has improved gloss and is coated with the coating agent. Along with physical properties, wear resistance,
Improves water resistance, etc.

[Problem to be solved by the invention]

However, in the method of the above-mentioned apparatus, after the coating agent is heated under pressure using a rotating roll and an endless belt, the coating agent must be cooled until it is discharged so that it can be easily peeled off from the belt. Must be. In order to perform this cooling sufficiently, it is not possible to increase the rotational speed of the belt, that is, the processing speed, and it is not possible to use a device consisting only of a pair of heat rolls, resulting in the problem that productivity cannot be improved. was.

In view of these circumstances, the present applicant proposed an improved coating composition with good releasability on the same date as the present application, and the present application proposes an improved coating composition with good releasability. The object of the present invention is to provide a method and an apparatus for carrying out the method.

[Means to solve the problem]

In order to solve the above problems, the present invention prints on the surface of a plate-like substrate, and coats the printed substrate surface with an acrylic resin having a glass transition temperature of 70 to 110°C and a phosphoric acid represented by the following general formula. Ester surfactant (in the formula, R1 represents an alkyl group or an alkylphenyl group, and n is 1 to
An integer of 50, R2 represents hydrogen, oxyethylene alkyl or oxyethylene alkylphenyl) is applied, and then the coated surface is heated and pressed by a heating and pressing means to form a glossy surface. The coating surface is configured to be peeled off from the heating and pressurizing means without forcing the coating surface to cool. or
A printing unit that prints on the surface of a plate-like substrate, an acrylic resin with a glass transition temperature of 70 to 110°C on the printed substrate surface, and a phosphate ester surfactant represented by the following general formula (in the formula R1 represents an alkyl group or an alkylphenyl group, n is an integer of 1 to 50, and R2 represents hydrogen, oxyethylene alkyl or oxyethylene alkylphenyl); The present invention is equipped with a press unit that heats and presses the coating film applied to the surface of the substrate using a heat roller and a pressure roller to form a glossy surface.

[Effect]

A web-like substrate that is continuously conveyed has a predetermined print on its surface, and then a coating agent containing a predetermined composition is applied to the printed surface, and then this coated surface is heated and pressed by a heating and pressing means. While being pressed to form a glossy surface, the coated surface is peeled off from the heating and pressing means without forced cooling.

〔Example〕

An apparatus for producing a base material having a glossy coating according to the present invention will be explained based on FIG.

As shown in FIG. 1, the manufacturing apparatus of the present invention includes, from the left side of the drawing, a printing unit P1, a coating agent applying unit C1, a press unit K, and further includes a cutter unit G as required.

The substrate as the workpiece is a printable plate-like object or a roll-like object that is transported from the left side to the right side of the drawing, such as a book cover, calendar paper, cardboard, carton, bag, etc. can be mentioned.

The printing unit P has, for example, a plate cylinder 2 and an impression cylinder 3 opposing the plate cylinder 2 as printing means, and a substrate is sandwiched between them, and as the plate cylinder 2 and the impression cylinder 3 rotate, the surface of the substrate is Printing is now possible. The printing means is not particularly limited as long as it is of the rotary type, and various means such as flexo printing, gravure printing, flat plate rotary printing, and rotary type screen printing can be used.

The printing ink used may be either water-based or solvent-based.

In addition, when performing multicolor printing, a plurality of such printing units P may be arranged in tandem.

The thus printed substrate is guided by several guide rollers and conveyed to the next coating agent application unit C.

This coating unit C has, for example, a coating agent application roller 4 and a pressure roller 5 opposed thereto as coating means, and thereby the coating agent is applied to the surface of the substrate printed in the previous step.

The coating agent used in the present invention contains an acrylic resin, and this acrylic resin has a glass transition temperature (
It is limited to those having physical properties in the range of 70 to 110°C (hereinafter simply referred to as Tg).

This is because high-temperature peeling becomes difficult if the Tg value is less than 70°C.On the other hand, the reason why the upper limit of Tg was set at 110°C is that this value is generally the upper limit of acrylic resin and is determined by itself. It is from.

Examples of such acrylic resins include polymerized resins of acrylic acid alkyl esters (CH2=CHCOOR') or methacrylic acid alkyl esters (CH2=CH3COOR'), where R' is methyl, ethyl, n
- Represents an alkyl group such as butyl, 1-butyl, t-butyl, 2-ethylhexyl, lauryl, etc. Also, one or a mixture of two or more of these various acrylic acid alkyl esters and methacrylic acid alkyl esters and copolymers of styrene, α-methylstyrene, acrylonitrile, methacrylonitrile, vinyl acetate, and vinyl chloride-vinyl acetate. Can be used as acrylic resin.

Such an acrylic resin can obtain surface smoothness by pressing, has good gloss releasability, and has good adhesion to both water-based and solvent-type gravure inks as underprint inks.

Furthermore, the coating agent contains a phosphate ester surfactant represented by the following general formula [1].

General formula [1] In the above general formula [1], R1 represents an alkyl group or an alkylphenyl group, and the alkyl group has 1 to 3 carbon atoms.
0, more preferably 12-15.

n is the number of moles of ethylene oxide added, and the value of n is an integer of 1 to 50, more preferably 3.

R is hydrogen, oxyethylene alkyl (R1(CHCH2
0)n) or represents oxyethylenealkylphenyl. Note that R1 and n have the same meanings as in the above case.

The phosphate ester surfactant represented by the general formula [1] is contained in an amount of 2.5 to 10 parts by weight based on 100 parts by weight of the acrylic resin.

When this value is less than 2.5 parts by weight, high temperature releasability deteriorates, and when this value exceeds 10 parts by weight, the smoothness of the coating film surface after pressing becomes poor. Such surfactants mainly function as mold release agents, have good high-temperature releasability, provide lubricity to the press coating surface, and improve wear resistance and
It is also effective in improving scratch resistance.

The acrylic resins and surfactants mentioned above are of the type that can be dissolved in organic solvents, and the organic solvents used include aromatics such as toluene, esters such as ethyl acetate, ketones such as methyl ethyl ketone, and isopropyl. One or more alcohol-based solvents such as alcohol can be used.

Furthermore, the coating agent contains 5 parts by weight of polyethylene wax, paraffin wax, microcrystalline wax, etc., which are usually used in printing inks, as an anti-wear agent per 100 parts by weight of the mixture of acrylic resin and organic solvent.
It is preferable to add it in a range of parts by weight or less. If it exceeds 5 parts by weight, the coating film becomes cloudy and has poor gloss.

Furthermore, as a surface smoothness improver, vinyl chloride/vinyl acetate copolymer (degree of polymerization 100 to 400, vinyl chloride/vinyl acetate ratio 50 to 150)
80/20) to a mixture of acrylic resin and organic solvent 1
It may be added in an amount of 15 parts by weight or less per 00 parts by weight. If it exceeds 15 parts by weight, high temperature releasability will deteriorate.

Other mold release agents include lecithin, fatty acids such as stearic acid, fatty acid esters such as n-butyl stearate, fatty acid amides such as stearamide, and one or two surfactants of partial esters of fatty acids and polyhydric alcohols. More than one seed may be added.

Note that the above coating agent can be applied to a workpiece printed with either a water-based ink or a solvent-based underprint ink without causing any problems.

As a coating means, in addition to the roll coating shown in this embodiment, curtain coating, spray coating, gravure printing, a flexo printing machine, or the like may be used, and the coating is applied to the entire surface of the substrate or a necessary portion. The coating amount is preferably 2 to 8 g/rl in solid weight.

The substrate coated with such a coating agent is guided by a predetermined number of guide rollers and conveyed to the next press unit K.

This press unit is equipped with heating and pressing means having a heat roll 50 and pressure rolls 51' and 55. Then, a heat roll 50 and a pressure roll 51. The heat roll 50 and the pressure roll 55 rotate while sandwiching the substrate, respectively, and heat and press the coating agent deposited on the surface of the substrate to form a glossy surface. The heat roll 50 is provided with a heating means (not shown), and the temperature of the heat roll 50 is 100 to 150°C, more preferably 105 to 120°C. heat roll 5
0 and the pressing force by the pressure roll 51.55 is 20 to 15
0kg/all, more preferably 30-100kg/a
n. If the temperature and pressing force of the heat roll 50 exceed the above-mentioned upper limit, peeling becomes difficult, and if it falls below the above-mentioned lower limit, sufficient gloss cannot be obtained.

In this embodiment, two pressure rolls are provided as heating and pressing means, but the present invention is not limited to this, and it goes without saying that the number of pressure rolls may be one or three or more.

FIG. 2 shows another embodiment of the press unit.

In Figure 2, heat roll 50 and pressure roll 51.
55 is similar to that shown in FIG. 1, but is fundamentally different in that guide rolls 115 and 116 are provided below the heat roll 50. That is, the substrate sandwiched between the heat roll 50 and the pressure rolls 51 and 51 is first separated from the heat roll 50, and is again sandwiched between the heat roll 50 and the pressure roll 55 and pressed. There is.

The coating thus applied to the surface of the substrate is heated and pressurized, and the base material having the glossy coating is carried into the cutter unit G as necessary and cut as appropriate.

Hereinafter, the present invention will be explained in more detail by showing experimental examples of the present invention.

Experimental Examples Various compositions 1 to 11 shown in Table 1 below were prepared by appropriately combining and blending the types of resins, mold release agents, antiwear agents, and solvents shown below.

(Resin) r-1; n-butyl methacrylate (7g 50°C) r-2; styrene acrylic resin (7g 92°C) r-3;
Acrylic-vinyl acetate copolymer resin (7g 64℃) r-4; Acrylic-vinyl acetate copolymer resin (7g 87℃
) r-5; Vinyl chloride-vinyl acetate copolymer resin (degree of polymerization 1
00. Vinyl chloride, vinyl acetate = 60 + 40) (mold release agent) m-1; In the phosphoric acid ester surfactant represented by the above general formula [1], R1 is an alkyl group having 13 carbon atoms, n is 3, and R2 is a hydrogen surfactant m-2; In the phosphate ester surfactant represented by the above general formula [1, R1 is) an engineering group, n is 6, R
Surfactant m-3 in which 2 is hydrogen; In the phosphoric acid ester surfactant represented by the above general formula [1], a surfactant m-3 in which R1 is a nonylphenyl group, n is 4, and R2 is hydrogen; 4; In the phosphate ester surfactant represented by the above general formula [1], R1 and R2 are nonylphenyl groups, and n is 7. Surfactant (anti-wear agent) Polyethylene wax (solvent) S-1, Toluene S-2; Ethyl acetate S-3; IPA\, Various composition samples shown in Table 1 were placed on a so-called polysand original fabric, which is a laminate of paper/polyethylene/paper, under the following press processing conditions. Coated with.

That is, as a pre-process, a water-based acrylic type ink was printed on a polysand raw fabric using a gravure printing machine, and then various composition samples shown in Table 1 were applied, and after that, 12
Pressure 100kg/an, speed 1 with hot roller at 0℃
Pressing was performed at a speed of 0 m/min to produce a coated sample. In addition, even if the printing with the above water-based acrylic ink as a pre-process is changed to printing with a nitrified cotton/polyamide resin-based solvent ink,
A sample was prepared in the same manner.

The following evaluations were performed on these samples. The evaluation items and their evaluation criteria are as follows.

(glossy) The 60° reflectance was measured and expressed as a percentage.

(Releasability) The state of peeling when pressed with a hot roller at 120°C was examined. The evaluation criteria were as follows.

◎...There is no peeling sound, or if there is, it is very small.O...There is no abnormality on the coating surface, but there is a peeling sound.△...There is peeling, but there are cracks on the coating surface. Formed: Coating film removed by roller (Surface smoothness) The pressed surface was visually judged. The evaluation criteria were as follows.

◎...Extremely smooth surface O...Slightly uneven smoothness △...Things with uneven smoothness (adhesion to royal ink) Sellotape peel test for pressed products I did it.

The evaluation criteria were as follows.

○...The royal ink adheres to both water-based and solvent types △...The lower ink only adheres to either water-based or solvent types ×...The lower ink adheres to both water-based and solvent types The results of those that did not adhere to both solvent types are shown in Table 2 below. Note that the sample numbers correspond to the composition numbers in Table 1.

Table 2 [Effects of the Invention] From the results in Tables 1 and 2 above, the effects of the present invention are clear.

That is, as described above, according to the method and apparatus of the present invention, not only gloss can be obtained on the surface of the substrate by so-called press processing, but also the coating composition can be easily peeled off from the heat roll while still in a high temperature state.

Therefore, unlike conventional methods, cooling for peeling is not required, and productivity is significantly improved.

[Brief explanation of drawings]

Figure 1 is a schematic front view of the manufacturing apparatus of the present invention, Figure 2 is a front view showing another embodiment of the press unit, and Figure 3 is a schematic diagram of a pair of clamping belt type press equipment used for surface processing. be. P... Printing unit, C... Coating agent application unit, K... Press unit, 50... Heat roller, 51.55... Pressure roller.

Claims (1)

[Claims] 1. Printing is performed on the surface of a plate-like substrate, and the printed substrate surface is coated with an acrylic resin having a glass transition temperature of 70 to 110°C and the following general formula ▲ mathematical formula, chemical formula, table, etc. There is a phosphate ester surfactant represented by ▼ (in the formula R_1
represents an alkyl group or an alkylphenyl group, and n is 1
An integer of ~50, R_2 represents hydrogen, oxyethylene alkyl or oxyethylene alkylphenyl) is applied, and then the coated surface is heated and pressurized by a heating and pressurizing means to form a glossy surface. Also, a method for producing a substrate having a glossy coating, characterized in that the coated surface is peeled off from the heating and pressing means without forcing the coated surface to cool. 2. The gloss according to claim 1, wherein the phosphate ester surfactant contained in the coating agent is contained in an amount of 2.5 to 10 parts by weight based on 100 parts by weight of the acrylic resin. A method for manufacturing a base material having a film. 3. The heating and pressing conditions by the heating and pressing means are 100 to 1
3. The method for producing a substrate having a glossy coating according to claim 1 or 2, wherein the coating temperature is 50°C and 20 to 150 kg/cm. 4. A printing unit that prints on the surface of a plate-shaped substrate, an acrylic resin with a glass transition temperature of 70 to 110℃ on the printed substrate surface, and the following general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ A phosphate ester surfactant (R_1 in the formula
represents an alkyl group or an alkylphenyl group, and n is 1
an integer of ~50, R_2 represents hydrogen, oxyethylene alkyl, or oxyethylene alkylphenyl); and a heating roller and pressurizing the coating film applied to the substrate surface. 1. An apparatus for producing a base material having a glossy coating, comprising: a press unit that heats and presses with a roller to form a glossy surface.