JPS58153632A - Sheet for forming printed sleeve - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sheet for forming printed sleeves, and an object of the present invention is to provide a material suitable for shrinkable sleeves used for covering and protecting glass bottles etc., and particularly suitable as a material for sleeves used after printing.

Conventionally, a sleeve made of a heat-shrinkable synthetic resin sheet is placed over the outer surface of a glass bottle, etc., and when heated, the sleeve shrinks due to K and is coated so as to closely fit the outer surface of the glass bottle, etc., to protect the glass bottle, etc. There are some things being done.

As the heat-shrinkable sheet forming the sleeve, for example, a foamed polystyrene sheet is widely used as it has excellent cushioning properties, but the foamed sheet has the drawback of poor surface smoothness and poor printability. No. 8, the sheet surface was easily scratched. In addition, when the glass bottles are continuously transported by a vibrating conveyor or the like after shrink-covering them with a sleeve, the glass bottles do not move smoothly because the surface is not smooth, and there is a risk that the bottles will stagnate in the middle of the travel path.

Therefore, the present invention solves the above-mentioned conventional drawbacks and provides a sheet for forming a printing sleeve that has excellent printability and durability of the printed surface during use. The non-foamed polystyrene film is laminated with a non-foamed polystyrene film, the non-foamed film contains 0.03 to 6.0 parts of polyethylene wax per 100 parts of the styrene resin, and the foamed sheet is laminated with the non-foamed polystyrene film. The shrinkage rate is larger and less than the skin %, the shrinkage rate in the width direction is less than 1096, and the shrinkage rate in the machine direction is greater than the shrinkage rate in the width direction, and both ends in the machine direction are joined with the foam sheet side facing inside. It is characterized by

Next, embodiments of the present invention will be illustrated below with reference to the drawings. 1 Printing sleeve forming sheet G) is a shrinkable foamed polystyrene sheet (1) and a shrinkable non-foamed polystyrene film (
2) are laminated, and both (1) and (!) have so-called heat-shrinkability, meaning that they shrink when heated.

The shrinkability is added by stretching during extrusion molding, and the magnitude of the shrinkage force or shrinkage rate varies depending on the molding conditions such as the amount of stretching or the composition of the resin material. In the case of foam sheet +11, resin skin layers are formed on both sides by extrusion foaming, but the thickness varies depending on the degree of cooling during molding. Therefore, the printing sleeve forming sheet (S) of the present invention can be formed by appropriately setting the above-mentioned molding conditions or the composition of the raw material.

First, the polystyrene resin that is the material of the foam sheet +11 includes vinyl aromatic resins such as styrene, vinyltoluene, isopropylstyrene, α-methylstyrene, nuclear methylstyrene, chlorostyrene, and tertiary-butylstyrene.
Styrene polymers obtained by polymerization of styrene monomers and alkyl acrylates such as 1,3-butadiene, butyl acrylate, ethyl acrylate, and 2-ethylhexyl acrylate, acrylonitrile, vinyl acetate, -α-methylethylene, A styrene copolymer containing 50% by weight or more of divinylbenzene and shimmer is used, and the resin is propane and butane.

isobutane, pentane, neopentane, impentane,
Aliphatic hydrocarbons such as hexane and butadiene; cycloaliphatic hydrocarbons such as cyclobutane, cyclopentane, and cyclohexane;
Raw hydrocarbons and blowing agents such as halogenated hydrocarbons such as methyl chloride, methylene chloride, dichlorofluoromethane, chlorotrifluoromethane, dichlorodifluoromethane, chlorodifluoromethane, and trichlorofluoromethane are added, and the mixture is heated and foamed. Foam sheet (1
) to form. The thickness of the foamed sheet (1) can be in the range of 0.1 to 1 mm, and if it exceeds IW, it becomes difficult to wind the sheet into a roll and cannot be shipped in a roll, which is not preferable.

As the non-foamed film (2), the above foamed sheet (1)
The same styrene resins as the materials can be used, and 0.03 to 6.0 parts of polyethylene wax is contained per 100 parts of these styrene resins.

Polyethylene wax is an ethylene low polymer produced by ethylene polymerization or polyethylene thermal decomposition.
In the case of this invention, the molecular weight is 500 to 15
Those with a molecular weight in the range of ρOO can be used, especially those with a molecular weight of 1ρOO to
One with lOρ00 is preferable. That is, the drop point (ASTM, n
5ac'l rating), a molecular weight of 1,000 or less lowers the above-mentioned drop point, reduces the biting of the screw during extrusion molding, and allows only a small amount of polyethylene wax to be mixed with the styrene resin, which is preferable. do not have.

On the other hand, if the molecular weight is 10ρ00 or more, the drop point becomes high and the miscibility with styrene resin becomes poor, which is not preferable. When the above-mentioned molecular weight range is expressed as a drop point value, a molecular weight in the range of about 50 to 150°C can be used, and preferably one in the range of 9 to 150°C is used.

The addition of the polyethylene wax to the non-foamed film (2) has the effect of improving the solvent resistance of the non-foamed film (2). In other words, when printed on a shrinkable sheet that is simply a laminated foam sheet and non-foam film,
The surface of the non-foamed film to be printed is partially attacked by the solvent of the printing ink. When this shrinkable sheet is used to form a sleeve and shrink-cover a bottle or the like, fine cracks will occur on the printed surface over time or due to changes in outside temperature. In this invention, the solvent resistance of the printing ink, which causes the cracking, is improved by containing the polyethylene wax.

The composition of the non-foamed film (2) is 0.03 to 6 parts of polyethylene wax to 100 parts of styrene resin.
．． If the content is less than 0.03 parts, the effect of improving solvent resistance will be small, and if it is more than 6.0 parts, the surface of the film will deteriorate and printability will deteriorate. Therefore, neither is preferable, and it is most effective to implement the content within the range of 0.03 to 4.0 parts.

In addition, the non-foamed film (2) can also contain a rubber component such as butadiene or butene, and by incorporating the rubber component, the non-foamed film (2)
When extruding and laminating the and foam sheet +11 at the same time,
This frees up the stretching of the non-foamed film (2).

This is temporarily a non-foamed film (2) and a foamed sheet + 11
If the shrinkage rate is the same as that of the non-foamed film, cracks will occur in the non-foamed film when this laminated sheet is used to form a sleeve and the plate is covered with shrinkage. In order to prevent this, it is necessary to make the shrinkage rate of the non-foamed film (2) 1\ smaller than that of the foamed sheet (1), and for this purpose, the stretching of the non-foamed film (2) can be controlled. It is effective to contain 4% of the rubber content in the non-foamed film (2), preferably 20% by weight or less, preferably 2% to 20% by weight.
The content is in the range of 10% by weight, and if it exceeds 20% by weight, it is undesirable because it is easily attacked by the solvent of the printing ink.

In addition, if the non-foamed film (2) contains a suppressant such as titanium white, it will reduce the light transmittance and increase the reflectance, so when laminated with the foamed film (2) +11, the coloring will be better during printing.
It has the effect of improving the gloss or luster of the surface, and the content of titanium white is preferably 5% by weight or less.

The thickness of the non-foamed film (2) is preferably in the range of 2 to 160 .mu.m. If the thickness is less than 2 .mu.m, the strength is weak and cracks are likely to occur during printing, and if it is more than 160 parts, the winding property becomes poor, which is not preferable.

The above-mentioned foamed sheet) ill and non-foamed film (2) are formed separately and then laminated by thermal adhesion etc. to form the printing sleeve forming sheet) (S). Any of the methods of laminating simultaneously with molding with the foamed film (2) can be used.

First, to explain the method using coextrusion, for example, in the case of inflation molding, the foam sheet (1) is on the inside,
The non-foamed film (2) is extruded from the extrusion die at the same time on the outside, and cooling air is applied to the foamed film (2) on the inside.
By applying air only to the ll side or by making the air on the foam sheet + 1) side particularly stronger than on the outside non-foam film (2) side, the cooling degree of the inside and outside is differentiated and stretched, and then taken off. to form an 811% sheet. The above-mentioned stretching causes shrinkage of the sheet (S) for forming a printing sleeve, but the foamed sheet (1), which has been cooled to a large degree, exhibits a larger shrinkage rate than the non-foamed film (2), and the foamed sheet +1+ itself Even if the air hits directly, a thicker skin layer is formed on the surface not laminated with the non-foamed film (2) (towards the river) than on the laminated surface (10) with the non-foamed film (2), and the shrinkage rate also decreases. In addition, by appropriately setting the take-up speed and blow-up ratio during stretching,
By controlling the amount of stretching in the machine direction and the width direction, the shrinkage rate in the machine direction of the laminated sheets can be kept below 60% and the shrinkage rate in the width direction is below 10%, and the shrinkage rate in the machine direction can be reduced to below 10%. The shrinkage rate should be greater than that of

The difference in shrinkage rate between the foamed film (fl) and the non-foamed film (2) is adjusted by adjusting the strength of the cooling air and by increasing or decreasing the rubber content contained in the non-foamed film (2).

Next, in the method of laminating by thermal adhesion, pre-foamed sheets)
+1+ and the non-foamed film (2) are extruded separately and the shrinkage rate of the foamed sheet (11) is larger than that of the non-foamed film (2) by adjusting the amount of stretching etc. Do it like this. Also foam sea) ＋
During extrusion molding (1), by varying the degree of cooling on both sides, the thickness and shrinkage rate of the skin layer can be adjusted (foaming sheet) +1
Make the front and back sides of 1 different. Furthermore, foam sheet (1)
The shrinkage rate in both directions can be adjusted by forming with a difference in the amount of stretching in the machine direction and width direction.

The foamed sheet 0) and non-foamed film (2) thus formed separately should be laminated by thermally adhering the non-foamed film (2) to the foamed sheet (10), which has a thin skin layer (11). Of the Nototo (formed printing sleeve forming sheet) (S), the amount of residual gas due to the foaming agent contained in the foamed sheet 11) is 2% by weight or less at the time of use, that is, at the time of heat shrinkage of the sleeve, which will be described later. I'll make an edict. This is to prevent the printing surface of the non-foamed film (2) from peeling off or cracking due to the increase in thickness of the sleeve due to expansion due to heating if there is a large amount of residual gas when the sleeve contracts. Although the residual gas gradually diffuses over time after extrusion molding, it is preferable to actively diffuse it using a heated roll or the like to control the residual gas.

As described above, foam sheet (1) and non-foam film (
The sheet (S) for forming a printing sleeve in which the above-mentioned sheets (S) and 2) are laminated is printed on the non-foamed film (2) side, and then cut into an appropriate size to form a cylindrical sleeve.

At this time, the foamed sheet 11) side of the printed sleeve-forming sheet (S) is turned to the inner surface, and the sheet is wound into a cylindrical shape so that the direction of flow is in the circumferential direction of the sleeve, and both ends of the sheet in the direction of flow are are joined by means such as thermal bonding to form a sleeve prisoner.

After putting this sleeve prisoner on a glass bottle (G), etc.,
``When heated, the sleeve (5) shrinks and tightly covers the glass bottle (G), thereby protecting the glass bottle (G).''
) is formed so that when it is placed over a glass bottle (1G), there is a gap of approximately 1 m between the glass bottle (1G) and the sleeve, which may cause adhesion if it shrinks, and may also affect the appearance. preferable. In addition, as the sleeve shrinks in the circumferential direction, it simultaneously becomes thicker in the thickness direction, but if this thickness change becomes extreme, the printed surface will become thinner due to the difference in the degree of shrinkage between the foam sheet (1) and the non-foam film (2). There are cases where it swells or cracks appear on the outside. Therefore, the size of the sleeve relative to the glass bottle (G) is adjusted so that the change in thickness is 2.0 times or less before and after shrinkage. The luxurious sleeve (4) can be used for various purposes such as protecting fragile items such as glass bottles, ceramics, etc.

Next, properties such as solvent resistance were measured for the above printing sleeve forming sheet, and the results were compared for sheets having different raw material compositions.

The sheet was manufactured using an inflated 1-inch extrusion method using simultaneous extrusion, using two extruders.
A foam sheet (
The raw materials for the non-foamed film (2) are melt-kneaded in the other extruder (screw diameter 45W*) (extruder temperature 130-190°C), and the tip of one extruder is connected to the other extruder. After connecting to the die of the extruder and coating the outer periphery of the other molten mixture with one molten mixture,
The amount of extrusion from the annular tip die with a slit width of 0.4 cm is 3.
It was extruded into a cylindrical shape at a pressure of 0 to 33 mm, passed over a plug with a diameter of 145 cm, and taken off at a speed of 16 m/-. After passing through the plug, the sheet is cut into two pieces, and then passed through a hot roll (diameter: 100 cm) with a surface temperature of 92°C to obtain a printing sleeve forming sheet (S). Then, printing is performed on the printing sleeve forming sheet (S) using an ordinary printing ink for foamed polystyrene sheets.

Composition of printing ink and solvent Alcohol 40% Toluene 12% Ethyl acetate 6% Pigment 20% Acrylic resin 15% Cellulose resin 7% Next, both ends of the printing sleeve forming sheet (S) in the flow direction are joined to form a sleeve. Preheat a glass bottle (for coating) at 68°C, and then
) is covered with the sleeve (5), then the oven temperature is 16.
Shrink coat the sleeve (A) by heating at 0° C. for 10 seconds.

Various tests were conducted during the above process and on the finished shrink coating, and the results are shown in Tables I and II below.

However, as for the composition of the foam sheet, butane is added as a blowing agent to 100 parts of polystyrene at 0% per liter of polystyrene.
In Examples ① to 0, styrene-butadiene copolymer (containing 6% butadiene) was added to 75 parts of polystyrene to form a non-foamed film.
High impact polystyrene resin (Hl
) and a mixed resin of 50 parts of polystyrene resin (PS) containing 5 parts of titanium white in 100 parts of polystyrene, using variously changed contents of polyethylene wax (PEwax), and compared [F] In Examples , 0, polystyrene resin (PS) containing 100 parts of polystyrene and 5 parts of titanium white is compared with polyethylene wax (PEwax) having different contents. Furthermore, the polyethylene wax (PEwax) in the above formulations has a molecular silver of 2000 and a drop point of 118°C.

○Tensile elongation tensilon test: sample shape dumbbell (width 10cm, length 40fl) room temperature, tensile speed 14□10 Inject solvent (toluene: alcohol =
l: Drop 1) once and measure the time until a hole appears.0 Appearance: Visually determine the flatness of the film surface.0 Print Finish: Visually determine ink coverage and unevenness during printing.0 Crack test bottle. After shrink coating, the time until cracks appeared on the surface was measured under various temperature conditions (〉30 days indicates that no cracks were observed even after 30 days or more.) From the above tables, The effect of containing polyethylene wax in the non-foamed film (2) and the preferable range of the polyethylene wax content (Examples 1 to 1) are clear.

According to the printing sleeve forming sheet of the present invention constructed as described above, the shrinkable foamed polymethyl □ sheet and the shrinkable non-foamed polystyrene film are laminated, and when formed into a sleeve, the sheet becomes the outer surface. The non-foamed film has a smooth surface and very good printability, and requires less printing ink. Furthermore, since the above-mentioned film has excellent strength and is resistant to scratches, combined with the excellent twilling properties of the inner foam sheet, it provides extremely excellent protection against glass bottles and the like. Therefore, even if the thickness of the glass bottle itself is koji-combed, it can withstand use sufficiently, making it possible to reduce the weight to approximately 1/2 of the conventional size, which is highly effective in reducing costs and transportation weight. It is.

Furthermore, since the above-mentioned film improves the surface lubricity, when glass bottles shrink-covered with sleeves are transferred using a vibrating conveyor, chute, etc., there is less frictional resistance when the glass bottles come into contact with each other, allowing smooth transfer. This eliminates the drawbacks of conventional foam sheet sleeves in which glass bottles tend to get clogged or stagnate in the middle of the travel path.

In addition, since the shrinkage rate of the foam sheet that forms the inner surface of the sleeve is greater than that of the non-foamed film that forms the outer surface, when shrink-covering a glass bottle, the inner foam sheet that requires a larger amount of shrinkage is applied to the glass bottle. It can be coated tightly, eliminating the occurrence of gaps or warping or curling at the shoulder or bottom of the bottle, and the bonding force to the glass bottle is sufficiently large.

Furthermore, since the foamed sheet itself has a thicker skin layer on the non-laminated side than on the laminated side with the non-foamed film, - first of all, it has good adhesion to glass bottles and can exhibit good effects in terms of shrinkage.

The shrinkage rate of the laminated sheets as a whole in the flow direction is greater than the shrinkage rate in the width direction, and when formed into a sleeve, the sheets are wound into a cylindrical shape so that the flow direction is in the circumferential direction of the sleeve, and both ends are joined. Then, when the sleeve is placed over a glass bottle and contracted, the sleeve mainly contracts only in the circumferential direction and hardly contracts in the axial direction, so that a predetermined range of the glass bottle can be sufficiently covered.

Furthermore, in this invention, since the non-foamed film contains polyethylene wax, it has solvent resistance that is not easily attacked by the solvent of the printing ink used when printing on the surface of the non-foamed film. Cracks do not occur on the printed surface due to aging or changes in outside temperature after shrink coating, and a beautiful exterior surface can always be maintained, resulting in extremely high commercial value.

As described above, it is possible to provide a sheet that is very suitable for forming printing sleeves that can exhibit excellent performance as a sleeve for shrink-coating glass bottles and the like.

[Brief explanation of the drawing]

The drawings illustrate an embodiment of the present invention; FIG. 1 is a sectional view, FIG. 2 is a perspective view of the sleeve, and FIG. 3 is a sectional view of the sleeve in use. (1)...shrinkable polystyrene foam), (SO)
... Laminated surface, (River... Non-laminated surface, (2)... Shrinkable non-expanded polystyrene film, (S)... Printing sleeve forming sheet, (P)... Sleeve, (G )・・
・Glass bottle. Figure 1 Figure 2 19

Claims (1)

[Claims] 1. A shrinkable foamed polystyrene sheet and a shrinkable non-foamed polystyrene film are laminated, and the non-foamed film has a content of 0.03 to 6.0% based on 100 parts of styrene resin.
The foamed sheet has a higher shrinkage rate than the non-foamed film, and its skin layer is thicker on the non-laminated surface than on the laminated surface with the non-foamed film, and Shrinkage rate in machine direction is 60
% or less, the shrinkage rate in the width direction is 1.0% or less, the shrinkage rate in the machine direction is greater than the shrinkage rate in the width direction, and printing is characterized by joining both ends in the machine direction with the foam sheet side facing inside. Sheet for forming sleeves. 2. A sheet for forming a printing sleeve according to claim 1, wherein the non-expanded polystyrene film contains 5% by weight or less of white titanium.