JPH05209348A - Polyolefin sheet coated with pearl pigment - Google Patents

Abstract

PURPOSE:To produce a sheet coated with a pearl pigment based on a polyolefin sheet having an excellent pearl feeling, no blocking and good printability and not giving a base deformation (irregurality, curl) caused by a high boiling petroleum solvent in a offset ink. CONSTITUTION:A 70g/m<2> polyolefinic spun bonded nonwoven fabric 1 (trade name Luxser H2070XW(R), produced by Asahi Chemical Industry Co., Ltd.) treated with corona discharge is coated with a coating liquid composed of 100 pts.wt. modified polyvinyl alcohol (trade name Gohsenal T-330(R), produced by the Nippon Synthetic Chemical Industry Co., Ltd.) and 10 pts.wt. ketone resin crosslinking agent (trade name Epinox P468L, produced by DIC Hercules Chemicals, Inc.) to make a barrier layer 3 against a high boiling petroleum solvent, and is further coated by 5g/m<2> with an adhesive coating made by adding 60 parts acrylic emulsion having 40 deg.C grass transition point, 30 parts acrylic emulsion having 20 deg.C glass transition point and 10 parts phosphorylated starch to 100 parts mica powder coated with titanic oxide having 40mum particle size by the extent of 28% coated ratio to form a pearl pigment coated layer 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pearl pigment-coated polyolefin sheet having a pearl pigment coating layer on one side or both sides of the polyolefin sheet, which does not cause blocking and has good printability.

[0002]

2. Description of the Related Art Since pearlescent pigment coated paper has a unique and beautiful appearance of pearly luster, it is used for publication of book covers, book counters, etc., for advertising of pamphlets, posters, etc., boxing, labeling and packaging. It has been used for stationery such as stationery. There have been many proposals in the past regarding this pearl pigment coated paper. For example, JP-B-39-29267 discloses that a basic lead carbonate-based pearl pigment is coated with an adhesive composed of casein and melamine-formaldehyde resin or urea-formaldehyde resin, synthetic resin latex,
In Japanese Patent Publication No. 51-45682, a base paper having a large number of textured and uneven distributions is coated with a pearl luster pigment. In Japanese Patent Publication No. 1-47597, an aqueous pigment coating layer is formed on a base paper. It has been proposed that an aqueous pearl pigment coating layer and a surface-treated layer containing a water-soluble polymer as a main component are sequentially provided on the above.

On the other hand, the performance requirements for pearl pigment-coated paper have become more and more sophisticated these days, but in all cases, the common requirements are aesthetically pleasing including pearly feeling. It may be excellent in effect and printability, particularly offset printability. In addition, the range of its use is wide, and not only paper but also synthetic resin sheet is required for the base sheet.

[0004]

DISCLOSURE OF THE INVENTION The present inventors have focused on a polyolefin-based spunbonded non-woven fabric, synthetic fiber paper or synthetic paper as a synthetic resin sheet, and produce a pearl pigment-coated polyolefin sheet using the same. In order to do so, we started to study. In the present invention, for convenience, a polyolefin-based spunbonded nonwoven fabric, synthetic fiber paper, or synthetic paper is referred to as a polyolefin sheet.

The polyolefin-based spunbonded nonwoven fabric comprises the steps of melting a polyolefin synthetic resin such as polyethylene and polypropylene, extruding it from a spinneret and spinning it, stretching and opening the fiber, forming a sheet, and forming a sheet. It is well known that it is manufactured by continuously performing the fixing process.

For example, as disclosed in Japanese Patent Publication No. 37-4993, a method of extruding and stretching a filament spun from a spinneret through a suction jet device to electrostatically open the filament to form a sheet, As proposed in Japanese Patent Publication No. 37-11293, a method of arranging a die in a ring shape, stretching with a roll, opening by static electricity and air jet injection, and thermocompression bonding, is proposed in US Pat. No. 3,578,739. The molten synthetic resin of high temperature and high pressure is released from the spinneret into the atmosphere, and the solvent is instantly foamed and evaporated to produce many fine filaments of complicated shape (flash spinning), which are opened by static electricity. , Sheeting and thermocompression bonding method, British Patent 10
There is known another method, such as that proposed in Japanese Patent No. 55187, in which filaments spun from a linearly arranged spinneret are stretched and opened by air jet injection to form a sheet and fixed with an adhesive.

Among spunbonded non-woven fabrics, fine fibers are used, and the fibers are bonded by thermocompression bonding, which is similar to the texture of paper and is tough and capable of printing to some extent. It is used for applications such as tags, labels, airmail envelopes, floppy disk sleeves, maps, and outdoor advertisements. The product name (trade name) is "Tyvek" from DuPont and "Luxar" from Asahi Kasei. Are well known. In the present invention, the form is preferably as close to paper as possible (so-called paper-like), with few pinholes and large surface smoothness.
A center line average roughness of 10 μm or less measured by a stylus meter is used. The basis weight is usually 30 to 200 g / m ² , and preferably 50 to 150 g / m ² . Also,
By applying glow (corona) discharge treatment, plasma treatment, flame treatment, etc. to the surface to enhance wetting suitability and applying a primer agent, it is possible to use a pearl pigment coating layer or solvent barrier layer to be applied next. Adhesion is also improved appropriately.

The polyolefin fiber paper is produced by using a polyolefin synthetic pulp or a polyolefin fiber alone or in combination with a heat-adhesive synthetic fiber, wood pulp or the like and using a paper machine or a non-woven fabric manufacturing apparatus. There is. Originally, the above-mentioned polyolefin synthetic pulp produced by the flash method or the like should be distinguished from the polyolefin fiber produced by the melt spinning method or the like, but in the present invention, for convenience, those both are included. Will be referred to as a polyolefin fiber.

The polyolefin-based synthetic paper is made of a stretched product of a polyolefin film or a film containing an inorganic powder in a polyolefin.
0794, JP-A-60-79951, and JP-A-61-161.
No. 3,748, JP-A No. 62-227933 and the like.

On the other hand, as is well known for printing art paper, coated paper, high-quality paper, synthetic paper, various films, etc., offset (lithographic) printing, letterpress printing, gravure (intaglio) printing, flexographic printing, screen printing, etc. Printing method is adopted. Offset printing is widely used because high-quality multicolor printing can be easily performed, plate making cost can be reduced, and even a small order can be made at a relatively low cost.
Since art paper, coated paper, and high-quality paper have excellent ink absorption, general-purpose offset printing ink can be used for non-water-absorbing materials such as synthetic paper and film, and the ink setting is quick, and the special quick-drying special ink is used. Offset printing inks, UV curable offset printing inks, and electron beam curable offset printing inks are often used. Table 1 shows examples of the compositions of commercially available general-purpose offset printing inks and quick-drying offset printing inks for non-absorbent materials.

[0011]

[Table 1]

As shown in Table 1, in general, quick-drying offset printing inks for non-absorptive materials have a high boiling point petroleum-based composition in which the proportion of drying oil is increased as an ink vehicle in order to shorten the drying time. The ratio of solvent is low and the amount of dryer is large. Polyolefin sheets are mainly composed of synthetic resins such as polyethylene and polypropylene, and have poor ink absorbency, so that they are often printed using a fast-drying offset printing ink. When printing on a non-absorbent material using a quick-drying offset printing ink, there are common problems such as difficult control of dampening water and settling countermeasures due to slow setting time. For this reason, printers tend to be reluctant to use fast-drying offset printing inks, which are difficult to handle.

Also, for quick-drying offset printing ink,
Although it has a lower ratio than general-purpose offset printing ink, it always contains a high boiling point petroleum solvent, and when it is used to print on a polyolefin sheet, it swells the base and causes partial printing on the surface after printing. Unevenness on the
It causes problems such as curling of the whole. In particular, this tendency is large in polyolefin resins such as polyethylene and polypropylene. It is presumed that this is because the molecular weights of the polyolefin resin and the high boiling point petroleum solvent are different, and the molecular structures are similar to each other. Further, when the printed matter is overlaid on a roll or sheet and the ink is dried, the solvent contained in the printed area is volatilized, causing the synthetic resin on the back side of the overlaid printed matter to swell, causing unevenness and curl. There is also.

In order to obtain a pearl pigment coating sheet in which a pearl pigment coating layer is provided on a polyolefin sheet, in simple terms, the pearl pigment coating liquid conventionally used should be applied to the base sheet. However, as a result of examination, it was found that this method causes a blocking problem. This tendency is particularly great when stacking sheets of paper after offset printing. What is blocking is when you stack multiple sheets of paper,
This is a phenomenon in which the paper surfaces in contact with each other stick to each other due to temperature, humidity, pressure, and the coating composition, and when this happens, it becomes a fatal problem that printing cannot be performed, the paper surface is destroyed, and the like. It was presumed that the reason why the blocking after offset printing was large in the polyolefin sheet base was that the percentage absorbed by the dampening water base used during printing was smaller than that in the paper base.

Further, as described above, it has been found that when offset printing is performed, the base swells due to the influence of the high boiling point petroleum solvent contained in the ink, causing problems such as unevenness and curl.

An object of the present invention is to solve these problems. That is, a polyolefin sheet having a good pearly feeling, no blocking, good printability, and no deformation (irregularities or curls) of the base due to the high boiling point petroleum solvent contained in the offset printing ink was used as a base. The purpose is to produce a pearl pigment coated sheet.

[0017]

As a result of intensive investigations, the present inventors have solved the above-mentioned problems by using two kinds of specific water-dispersible resins and a water-soluble polymer compound as an adhesive. Yes, and here is the greatest feature of the present invention. That is, the gist of the present invention will be described with reference to the drawings. 100 parts by weight of pearl pigment (representing dry parts by weight, the same applies hereinafter) to a water-dispersible resin 1 having a glass transition point of 40 ° C. to 80 ° C. To 3 parts by weight, 0.5 to 3 parts by weight of a water-dispersible resin having a glass transition point of 20 ° C. or less, and 10 to 50% of a water-soluble polymer compound to the water-dispersible resin are mixed. A pearl pigment-coated polyolefin sheet in which the pearl pigment-coated layer 2 is formed on one side or both sides of the polyolefin sheet 1 with a coating material obtained by mixing 100 to 500 parts by weight of the adhesive agent. Further, a barrier layer 3 of a high boiling point petroleum solvent contained in the offset printing ink is provided under the pearl pigment coating layer 2 to obtain a pearl pigment coating polyolefin sheet.

The pearl pigments which can be used in the present invention are natural pearl essence, mica powder, basic carbonate, titanium oxide-coated mica powder and the like. In order to obtain the adhesion strength to the base paper, ink acceptability, and the desired pearly luster, the particle size and titanium oxide coverage must be selected, but the selection range is the widest, so use titanium oxide-coated mica powder. Preferably. The effective particle size is 5 to 150 μm, more preferably 10 to 100 μm. For example, titanium oxide-coated mica powder is disclosed in JP-B-53-47375 and JP-B-5.
It is produced by the method described in JP-A No. 4-34010, JP-A No. 58-149959, or the like.

The water-dispersible resin used in the present invention means acrylic acid or its ester, methacrylic acid or its ester, emulsion polymerization or emulsion copolymerization of vinyl chloride, vinylidene chloride, vinyl acetate, acrylonitrile, butadiene, styrene and the like. It is a water-dispersible emulsion (latex) and also includes a polymer having a functional group such as a carboxyl group or a hydroxyl group introduced therein.

The coating layer of the water-dispersible resin generally has high tackiness when the glass transition point of the resin is low, and becomes low when the glass transition point is high. Therefore, in order to prevent blocking, a water-dispersible resin having a high glass transition point may be used, but the use of this alone reduces the adhesive strength. On the other hand, when a water-dispersible resin having a low glass transition point is used alone, the adhesive force is obtained but the blocking problem occurs. As a result of further investigations by the present inventors, 1 to 3 parts by weight of a water-dispersible resin having a glass transition point of 40 ° C. or higher and 80 ° C. or lower is used, and a water-dispersible resin having a glass transition point of 30 ° C. or lower is used as an additive. It has been found that by mixing 5 to 3 parts by weight, a pearl pigment-coated polyolefin sheet having a practically sufficient adhesive force and causing no blocking can be obtained.

However, if only the water-dispersible resin is used for the adhesive, the water absorbency of the coated surface is insufficient, and if it is left as it is, the printability, especially the offset printability, which is an important performance as a pearl pigment coated sheet, is insufficient. understood. It was also found that the above-mentioned offset printing causes the problem of unevenness and curl after printing due to the influence of the high boiling point petroleum solvent contained in the ink.

As is well known in offset printing, dampening water is used at the time of printing, but it is preferable that the paper surface of the printing paper absorbs this water appropriately. If the water absorbency of the paper surface is insufficient, the ink is easily emulsified. , Causes trouble called scumming. The present inventors have solved these problems by mixing the water-soluble polymer compound with the water-dispersible resin at a ratio of 10 to 50%.

The present inventors first dissolved various water-soluble polymers in water and determined the concentration when the viscosity was adjusted to 100 CPS. In addition, pearl pigment coated sheets were prepared by changing only the type of water-soluble polymer, and the water absorption of the paper surface and the barrier properties of high boiling petroleum solvents were compared. The results are shown in Table 2.

[0024]

[Table 2]

As the water-soluble polymer compound, starch or its derivative, carboxymethyl cellulose (CMC),
Known materials such as fibrin derivatives such as hydroxyethyl cellulose (HEC), casein, polyvinyl alcohol (PVA) and the like can be used. However, casein has a great effect of emulsifying the ink during offset printing, and causes troubles of scumming in some cases, and starch, a fibrin derivative and polyvinyl alcohol have a practical dissolved concentration as shown in Table 2. Since it is low, it is difficult to set the paint concentration to the optimum concentration, and water absorption is often poor. In the present invention, taking into account the balance with the solvent barrier property, it is preferable to use a starch derivative having a relatively high dissolved concentration and excellent water absorbability as the water-soluble polymer. Examples of the starch derivative include oxidized starch, dialdehyde starch, cationized starch, acetylated starch, phosphate esterified starch,
Known products such as hydroxyethylated starch can be used.
The water-soluble polymer compound is 10 to 50% of the water-dispersible resin,
Preferably, it is added in an amount of 20 to 30%. If it is less than this ratio, water absorption is insufficient, and if it is too large, the surface strength is insufficient.

In the present invention, 100 to 500 parts by weight of the pearl pigment is added to 100 to 500 parts by weight of the adhesive mixed in the above range to form a paint on one or both sides of the base sheet. If the amount of the adhesive is less than 100 parts by weight, the strength of the coating layer will be insufficient, and if it exceeds 500 parts by weight, the pearlescent feeling will be insufficient. The pearlescent pigment coating is prepared by adding a pearlescent pigment, for example, titanium oxide-coated mica powder to a tank in which the adhesive is gently mixed and stirred. Since vigorous stirring may destroy the mica powder, it is preferable to rotate gently.

At this time, it is possible to add auxiliary materials such as colorants such as dyes and pigments, waterproofing agents and viscosity modifiers to the coating material depending on the purpose. The pearl pigment paint prepared as described above,
The base is coated with an air knife coater, roll coater, blade coater or the like, but it is preferable to coat with an air knife coater in order to obtain a uniform distribution state of the pearl pigment in the coating layer. The coating layer may be formed by a paint having the same formulation on the front and back sides, or may be formed by different formulations. In particular, it is possible to further enhance the design effect by using pearl pigments having different particle diameters or hues or adding a colorant to form different hues. The coating amount is usually ² to 20 g / m ² on one side, but 5 to 8 g / m ² is preferable in order to obtain an effective pearly luster.

Further, in the present invention, a solvent barrier layer 3 is provided below the pearl pigment coating layer in order to further enhance the performance of preventing the deformation of the base due to the influence of the high boiling point petroleum solvent contained in the offset printing ink. You can also For the solvent barrier layer, it is effective to use a cross-linked polyvinyl alcohol or an acrylonitrile copolymer containing 20 to 55% by weight of acrylonitrile. The cross-linking type polyvinyl alcohol is a polyvinyl alcohol having a saponification degree of 65 to 100% or a modified polyvinyl alcohol modified by a carboxyl group, methyl methacrylate copolymerization, acrylamide copolymerization or the like as a crosslinking agent, and an inorganic substance such as boric acid or borax. System crosslinking agent, glyoxal, dialdehyde, N-methylol urea, N-methylol melamine,
It can be obtained by drying a liquid containing an epoxy resin such as epichlorohydrin, a dicarboxylic acid, a polycarboxylic acid and the like. It is considered that the cross-linking makes the molecular structure of polyvinyl alcohol dense and increases the effect of preventing penetration of the high boiling point petroleum solvent.

Acrylonitrile copolymers containing 20 to 55% by weight of acrylonitrile include acrylonitrile 2
0-55% by weight, acrylic acid esters such as methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylic acid, methyl methacrylate,
Methacrylic acid esters such as ethyl methacrylate, butyl methacrylate and glycidyl methacrylic acid, and unsaturated carboxylic acids such as acrylic acid, methacrylic acid and itaconic acid, acrylamide, methacrylamide, acrylonitrile, styrene, α-methylstyrene, acetic acid There are copolymers with 80 to 45% by weight of other vinyl monomers such as vinyl, and the emulsion obtained by the emulsion polymerization method is preferably used in the present invention.

In the present invention, alkylbenzene sulfonate, polyethylene oxide alkyl ether sulphate, etc. added at the time of polymerization are added in order to improve the adhesion to the base and the adhesion to the pigment coating layer and to improve the solvent resistance. It is preferable that the addition amount of the anionic surfactant and the nonionic surfactant such as polyethylene oxide alkyl ether and polyethylene oxide alkylphenol ether be as small as possible. The amount of these activators added is usually 2% by weight or less based on the monomer,
It is preferably 1% by weight or less.

The above emulsion used in the solvent barrier layer in the present invention is prepared by a conventional method. As an example, a predetermined water, an activator, and a monomer are put in a reaction kettle, and a redox-based initiator in which potassium persulfate, ammonium persulfate, hydrogen peroxide, and the like are combined with sodium sulfite and the like as a polymerization initiator. 0.1 to 2% by weight
In addition, the reaction is performed at a temperature of 50 to 90 ° C.

Acrylonitrile serves to impart solvent resistance to the film and toughness, heat resistance and heat shrinkage resistance. If the amount of acrylonitrile is less than 20% by weight, the solvent barrier property becomes poor, and if it exceeds 55% by weight, blocking tends to occur greatly, so it is necessary to be in the above range.

In the present invention, the solvent barrier layer contains an inorganic pigment, a coloring agent, a crosslinking agent,
A fluidity improver and the like can be added. The coating liquid thus prepared is coated on the base using a known air knife coater, blade coater, gravure coater, roll coater, or the like. The coating amount is generally 3 to 2
5 g / m ^2, preferably from 5 to 15 g / m ^2.

[0034]

The present invention will be described in detail with reference to the following examples. Unless otherwise specified, parts by weight means dry parts, and g / m ² also means dry weight. Coating base base. 1 70g / m ² polyolefin spunbonded non-woven fabric with corona discharge treatment on both sides (trade name Luxer H
2070XW, manufactured by Asahi Kasei). base. 275 g / m ² polyolefin synthetic paper (trade name YUPO F
PG-95, Oji oil synthetic paper). Prescription of solvent barrier layer . 1 Modified polyvinyl alcohol (Brand name Gohsenal T-3
30, manufactured by Nippon Synthetic Chemical Industry) 10 parts by weight of a ketone resin cross-linking agent (trade name: Epinox P468L, manufactured by Dick Hercules) in 100 parts by weight. Prescription. 2 40 parts by weight of acrylonitrile 40 parts by weight, butyl acrylate 50 parts by weight, carboxylic acid 10 parts by weight 40% of a mixed solution and anionic activator (sodium lauryl sulfate) 0.2 parts by weight
125 parts by weight of water was placed in a reaction vessel, and then the reaction system was purged with nitrogen gas, and a polymerization initiator (ammonium persulfate) 0.5
Parts by weight were added. When the polymerization reaction starts, raise the liquid temperature to about 60 ° C.
The remaining monomer was added dropwise over 2.5 hours while maintaining the above. After that, the temperature was raised to 85 ° C. and kept for 1 hour. After cooling to room temperature, sodium hydrogen carbonate was added as a buffer to 0.0
4 parts by weight was added, and pH was adjusted to 7 to 8 with aqueous ammonia to obtain an acrylonitrile emulsion having a solid content of about 45% by weight. Prescription of pearl pigment coating layer . 1 Mica powder 10 with a particle size of 40 μm and titanium oxide coverage of 28%
A coating material was prepared by adding 0 part (dry weight part, the same hereinafter) of 60 parts of an acrylic emulsion having a glass transition point of 40 ° C., 30 parts of an acrylic emulsion having a glass transition point of 20 ° C., and 10 parts of phosphorylated starch as an adhesive. Prescription. 2 Mica powder 10 with a particle size of 40 μm and titanium oxide coverage of 28%
A coating material was prepared by adding 0 part (dry weight part, the same hereinafter) of 60 parts of an acrylic emulsion having a glass transition point of 40 ° C. and 30 parts of an acrylic emulsion having a glass transition point of 20 ° C. as an adhesive.

Table 3 shows the formulation, constitution, and evaluation results of each example and comparative example. The evaluation was displayed in four levels of ◎, ○, △, × (excellent, good, good, and bad). For evaluation of printability (ink acceptability, stain resistance, ink setting property), a sheet is cut into quarter cuts and an offset printing machine is used to print a general-purpose offset printing ink (product name graph G type process ink, It was performed by printing with a Dainippon Ink Manufacturing Co., Ltd.) and a quick-drying ink (synthetic paper ink, Toyo Ink Manufacturing). The deformability of the base due to the ink was visually checked for the presence or absence of unevenness and the occurrence of curl after 500 sheets of this printed material were piled and left for 1 hour.
Blocking resistance is determined by the degree of blocking after contacting the paper surfaces at 40 ° C. and 90% RH and applying a pressure of 500 g / cm ² for 24 hours, and water absorption is determined by the degree of hump size (2 minutes). Then, the surface strength was judged by performing solid printing with the ink of Tack 30 using an IGT tester and observing the peeled state of the paper surface.

[0036]

[Table 3]

[0037]

As described above, the pearl pigment coated sheet of the present invention is constituted and has the following remarkable effects. Blocking does not occur even when papers are stacked, and printability is good. With the composition in which the pearl pigment coating layer is formed on both sides of the base sheet, it is possible to exert an unprecedented design effect, and it is suitable for applications such as posters, calendars, cut-off book covers, facings, menus, catalogs, greeting cards, etc. Available. By applying the anchor coat having the solvent barrier, it is possible to prevent the sheet from being deformed due to the influence of the high boiling point petroleum solvent in the ink even in the offset printing.

[Brief description of drawings]

FIG. 1 is a partially enlarged cross-sectional view of a pearl pigment-coated polyolefin sheet of the present invention (type provided with a high boiling point petroleum solvent barrier layer).

[Explanation of symbols]

 1 polyolefin sheet 2 pearl pigment coating layer 3 high boiling point petroleum solvent barrier layer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location D21H 19/36 13/14 7211-4J C09D 5/36 PRD 7199-3B D21H 5/20 B

Claims (3)

[Claims] 1. To 100 parts by weight of a pearl pigment, 1 to 3 parts by weight of a water-dispersible resin having a glass transition point of 40 ° C. to 80 ° C., and 0.
100 parts of an adhesive obtained by mixing 5 to 3 parts by weight and a water-soluble polymer compound in a ratio of 10 to 50% with respect to a water-dispersible resin.
A pearl pigment-coated polyolefin sheet, characterized in that the pearl pigment-coated layer 2 is formed on one side or both sides of the polyolefin sheet 1 with a paint mixed in an amount of up to 500 parts by weight. 2. The pearl pigment-coated polyolefin sheet according to claim 1, wherein the water-soluble polymer compound is a starch derivative. 3. The pearl pigment coated polyolefin according to claim 1, wherein a barrier layer 3 of a high boiling point petroleum solvent contained in the offset printing ink is provided below the pearl pigment coated layer 2. Sheet.