JP2001172407A - Substrate film comprising high density polyethylene resin and used for marking and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate film which comprises a high density polyethylene resin, has smooth surfaces, a uniform thickness and good cuttability, does not leave a non-cut portion, when the film is notched with a cutter to leave a prescribed letter or mark on a separator, and is used for marking, and to provide a method for producing the substrate film for marking, characterized by calendering the high density polyethylene resin as a substrate resin. SOLUTION: This substrate film is used for marking, has a thickness of 40 to 150 μm and comprises a resin composition comprising 100 pts.wt. of a high density polyethylene resin having a melt flow rate in a range of 0. 03 to 1.0 g/10 min and 3 to 30 pts. wt. of calcium carbonate having an average particle diameter of 0.05 to 2 μm. The substrate film for marking can be obtained by calendering the above-resin composition into the film having a thickness of 40 to 150 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a base film for a marking film made of a high-density polyethylene resin (hereinafter, referred to as a marking base film) and a method for producing the film by calendering.

[0002]

2. Description of the Related Art A marking film is obtained by laminating a pressure-sensitive adhesive layer and a separator (release paper) in this order on the back surface of a resin film that has been printed or colored in advance, and then using a cutting device equipped with a blade. This refers to a laminated film with an adhesive formed by making a cut on a separator so as to leave required characters, symbols, and the like, and then peeling off and removing other portions. When using such a marking film, the above-mentioned required characters and symbols are peeled off from the separator, and the adhesive is used on the back surface of the separator, and this is attached to an appropriate adherend, for example, a wall, a signboard substrate, or the like. Thus, for example, various names, symbols, numbers, and the like are displayed on the adherend.

Conventionally, a vinyl chloride resin film has been used as such a base film for marking. In particular, a film for marking is used when a film in the shape of characters or symbols shrinks with time. The pressure-sensitive adhesive partly protrudes from the film, and dust and dirt adhere to it, resulting in poor appearance. Conventionally, a casting method (casting method) that can obtain a film without such shrinkage occurs. Manufactured.

That is, as a method for producing a resin film, particularly, a vinyl chloride resin film, a calender method excellent in productivity has been well known. However, according to this calendering method, unevenness in the thickness called a bank mark or a flow mark may occur in a film due to uneven flow of a bank formed between calender rolls when passing through a roll gap. Such unevenness in thickness causes unevenness in color due to light transmitted through the film and unevenness in gloss due to reflected light. In the production of a film by calendering, a certain amount of tension is applied when the film is pulled from a calender roll, so that the obtained film is somewhat stretched, resulting in shrinkage. Therefore, it has been conventionally considered that calender molding is not suitable for a marking film base material requiring high precision in size and shape.

[0005] Under such circumstances, since vinyl chloride resin contains chlorine, various film products, including marking films, are made of a film made of vinyl chloride resin in view of growing environmental problems in recent years. The use of films made of polyolefin resins such as polyethylene and polypropylene is increasing.

However, conventionally, a film made of a polyolefin resin is formed by extruding a molten resin from a T-die to obtain a smooth film, or by pressing a molten resin from a ring-shaped circular die into a tube. It is manufactured by an inflation method in which compressed air is blown into the tube at the same time as it is taken out and the tube is expanded to obtain a tubular film. However, the productivity is low according to the T-die method, while the film is wavy according to the inflation method, which is not suitable for adhesive processing.

Further, the above-mentioned T-die method has the above-mentioned problems and is generally suitable for continuous production of a single film in large quantities. However, as in the production of a marking film, the T-die method has various colors. It is not suitable for manufacturing different products, that is, for producing multicolor and multiproduct. In particular, in the T-die method, at the time of color change, a small amount of the kneaded material used in the production of the previous film stays in the barrel of the extruder, and in order to remove this, much time is required for step change. It costs.

Therefore, in the production of a film made of a polyolefin resin, calendering is required as in the production of a conventional ordinary vinyl chloride resin film. However, in the calendering, a polyethylene or polypropylene resin is used as a raw material. If these resins are melted, the viscosity is low and the stickiness is remarkable if they are melted. Sticks to attached equipment and does not peel off (ie
Rolling occurs and it is difficult to produce a film with a smooth surface with good thickness accuracy, and in some cases even a continuous film. Further, even if the resin is semi-molten, a smooth film cannot be obtained.

Further, in general, unlike the T-die method in which a resin is heated and melted in a closed system using a kneading machine and extruded from a T-type die to form a film, the resin is opened in a calendering process. Since the film is heated, melted, and rolled between rolls to form a film, it is difficult to keep the temperature of the resin uniform.

[0010] Thus, in order to calender a resin, it is necessary that the resin has a viscosity suitable for processing in a wide temperature range.
The temperature range having a viscosity suitable for processing is narrow, and in this regard, calendering is conventionally considered to be difficult.

In addition, when the base film for marking is manufactured as described above, the polyolefin resin film has a large elongation at break, and if there is an acute-angled portion that resembles characters, symbols, etc., uncut portions are generated there. Inferior in cutting properties, it is conventionally considered unsuitable as a substrate film for marking.

[0012]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems in the production of a marking base film made of a high-density polyethylene resin. , Rolled by calendering high density polyethylene resin with a marking base film that has a smooth surface and uniform thickness, and has no cutting residue when cutting with a blade, and has excellent cutting properties. An object of the present invention is to provide a method for producing such a base film for marking without taking off from a roll with good take-off.

[0013]

According to the present invention, 0.03
A resin composition containing 3 to 30 parts by weight of calcium carbonate having an average particle size of 0.05 to 2 μm with respect to 100 parts by weight of a high-density polyethylene resin having a melt flow rate in a range of from about 1.0 g / 10 minutes. , Thickness is 40 ~ 150μm
Is provided.

Such a marking base film is
In accordance with the present invention, a high density polyethylene resin 100 having a melt flow rate in the range of 0.03-1.0 g / 10 minutes.
It is obtained by calendering a resin composition containing 3 to 30 parts by weight of calcium carbonate having an average particle diameter of 0.05 to 2 μm with respect to parts by weight to form a film having a thickness in the range of 40 to 150 μm. Can be.

[0015]

DETAILED DESCRIPTION OF THE INVENTION In the present invention, as is well known, a high-density polyethylene resin has a density produced by a so-called middle-low pressure method of 0.94 to 0.97 g / cm ^3.
In particular, according to the present invention, according to the method described in JIS K 6760, the melt flow rate measured at a temperature of 190 ° C. and a load of 2.16 kgf is from 0.03 to Those having a range of 1.0 g / 10 minutes are used.

When the melt flow rate of the high-density polyethylene resin exceeds 1.0 g / 10 minutes, even if the roll temperature is lowered, the melt viscosity is too low, and the resin sticks to the roll. The surface of the obtained film is tacky (sticky), making it difficult to obtain a film having a smooth surface. In particular, according to the present invention, the high-density polyethylene used has a melt flow rate of 0.1 to 0.1.
Those having a range of 0.8 g / 10 minutes are preferably used.

In the present invention, as long as the high-density polyethylene resin has a melt flow rate within the above range, two or more such high-density polyethylene resins may be mixed and used.

The base film for marking according to the present invention is a resin composition containing 3 to 30 parts by weight of calcium carbonate having an average particle diameter of 0.05 to 2 μm with respect to 100 parts by weight of the above-described high-density polyethylene resin. And the thickness is in the range of 40 to 150 μm. When the average particle size of the calcium carbonate used is smaller than 0.05 μm, even if it is mixed with a high-density polyethylene resin, the cutting property is hardly improved. On the other hand, when the average particle size of the calcium carbonate used is larger than 2 μm, a film having a smooth surface which can be used as a marking base film cannot be obtained.

When the proportion of calcium carbonate in the high-density polyethylene resin is too small, the cutting property of the film is hardly improved. Is insufficient, making it difficult to peel off from the roll,
Further, the film is easily cut, and the film cannot be pulled from the roll.

Further, the thickness of the substrate film for marking according to the present invention is preferably in the range of 40 to 150 μm. When the thickness is too thin, when cutting out characters and patterns from the resulting film as described above, since the film has holes, it is not suitable for use as a base film for marking,
On the other hand, when it is too thick, it becomes difficult to cut out characters and patterns from the film as described above, and the obtained film is too hard, so that the adhesion to the adherend is poor.

According to the present invention, the high-density polyethylene resin may be blended with various additives conventionally used in polyethylene resins, if necessary. Such additives include, for example, lubricants, heat stabilizers, light stabilizers, antioxidants, ultraviolet absorbers, pigments, modifiers, flame retardants, antistatic agents, reinforcing agents, tackifiers, fillers And a fungicide and the like.

The base film for marking according to the present invention comprises a high-density polyethylene resin composition containing calcium carbonate having a predetermined average particle diameter in a predetermined ratio, and has a smooth surface and elongation at break. Owing to excellent cutting properties.

According to the present invention, a conventionally known surface treatment such as a corona discharge treatment, a plasma treatment, a flame treatment or the like may be applied to the film, if necessary, in order to improve the adhesiveness and printability of the film. May be applied.

By providing an adhesive layer and a separator on the back surface of such a film, the marking base film according to the present invention can be obtained.

The pressure-sensitive adhesive is not particularly limited as long as it has been conventionally used in a pressure-sensitive adhesive film.
Acrylic, synthetic rubber-based or silicone-based pressure-sensitive adhesives are used, and among them, acrylic pressure-sensitive adhesives having excellent adhesion to a metal substrate are preferably used.

Such acrylic pressure-sensitive adhesives mainly include long-chain alkyl esters of (meth) acrylic acid which form a polymer having a low glass transition temperature, for example, 2-ethylhexyl acrylate, isobutyl acrylate, isononyl acrylate and the like. As a monomer component, in order to provide cohesion, if necessary, short-chain alkyl esters of (meth) acrylic acid, for example, methyl (meth) acrylate,
Ethyl (meth) acrylate or the like, or a vinyl ester such as vinyl acetate or the like is used as a comonomer component, and further, if necessary, as a further comonomer component to provide a crosslinking point, It can be obtained by using a hydroxyalkyl (meth) acrylate such as (meth) acrylic acid or hydroxyethyl (meth) acrylate and copolymerizing these. That is, such a monomer component is an appropriate organic solvent, for example, an aliphatic hydrocarbon, an aromatic hydrocarbon, an aliphatic carboxylic acid ester, specifically,
For example, a so-called solvent-type acrylic pressure-sensitive adhesive can be obtained by copolymerization in an organic solvent such as ethyl acetate or toluene.

Further, according to the present invention, the pressure-sensitive adhesive may contain a crosslinking agent. Examples of the crosslinking agent include modified polyisocyanates such as tolylene diisocyanate trimethylolpropane (for example, Coronate L manufactured by Nippon Polyurethane Industry Co., Ltd.), and chelators such as aluminum trisethyl triacetate. it can. In this way, the pressure-sensitive adhesive containing a crosslinking agent
After coating on the base film, drying, heating, and crosslinking of the pressure-sensitive adhesive, the pressure-sensitive adhesive strength can be adjusted.

However, according to the present invention, the pressure-sensitive adhesive is not limited to the solvent type, and if necessary, an aqueous pressure-sensitive adhesive such as an aqueous solution or an emulsion can be used.

The means for applying the pressure-sensitive adhesive to the base film is not particularly limited. For example, the pressure-sensitive adhesive may be coated on a release paper so as not to cause unnecessary expansion of the base film. After applying and drying the solvent, it is preferable to use a transfer method in which this is adhered to a base film and the adhesive is transferred from the release paper to the base film. However, an appropriate coating means such as a micron bar coater can also be suitably used.

The thickness of the pressure-sensitive adhesive layer of the base film should be such that sufficient adhesion between the base film and the base material is ensured so as not to protrude from the outside of the film in the form of characters, patterns, etc. Usually 2 so that you can gain strength
It is in the range of 0 to 60 μm, and particularly preferably in the range of 30 to 50 μm.

According to the present invention, as described above, the above-mentioned additives are blended, if necessary, with a resin composition in which calcium carbonate is blended at a predetermined ratio in a high-density polyethylene resin. The product is usually mixed with a continuous kneader, a Banbury mixer, a kneader, an extruder, etc., for 150 to 2 parts.
By heating and melting at a temperature of 00 ° C., kneading, and calendering the kneaded material, the marking base film according to the present invention can be obtained without being rolled up and with good roll-off properties. Here, the temperature of the calender roll is usually 150 to 220 ° C., preferably,
It is in the range of 160 to 190 ° C.

In this way, the above resin composition is rolled into a film having a required thickness by a calender roll, and if necessary, is rolled with a metal, usually steel, provided with a required squeezing pattern. The film may be guided to an embossing device composed of a combination of an embossing roll (rolled roll) and a heat-resistant semi-rigid rubber roll (pressure roll) for backing up the embossing roll to emboss the film.

Thus, the marking base film obtained according to the present invention has a smooth surface, is beautiful, has a uniform thickness, does not have citron skin, and has excellent cutting properties. .

[0034]

EXAMPLES The present invention will be described below with reference to examples.
The present invention is not limited by these examples.

Example 1 (Production of base film) High density polyethylene resin 100
Antioxidant (Irganox 1 made by Ciba-Geigy)
076) 0.2 parts by weight and 0.2% calcium stearate lubricant
Parts by weight, and further, calcium carbonate in the amount shown in Table 1 was blended to obtain a resin composition, which was kneaded and melted at a temperature of 150 to 180 ° C. The temperature is supplied to the calender and the roll temperature is 160 to 19
The film was rolled at 0 ° C. into a film having a predetermined thickness. Here, the term “roll” refers to all rolls that form four inverted L-shaped rolls, but not all rolls need to be at the same temperature.
What is necessary is just to be in the said temperature range.

In Table 1, all of the high-density polyethylene resins are manufactured by Mitsui Chemicals, Inc. and have a melt flow rate of 5000SR (test temperature 190 ° C., test load 2.16).
kgf, hereinafter the same. ) Is 0.35 g / 10 min and 3
The melt flow rate of 300F is 1.1 g / 10 minutes, and the melt flow rate of 5000SF is 0.65 g / 1.
0 minutes. In addition, calcium carbonate is manufactured by Takehara Chemical Industry Co., Ltd., and Neolite SRT has an average particle size of
0.15 μm, Sunlight SL2000 has an average particle size of 1.4
μm, Sunlight SL700 has an average particle diameter of 4.5 μm, and Neolite SS has an average particle diameter of 0.04 μm.

In the production of such a film by calendering, the calenderability of the resin composition and the smoothness of the surface of the obtained film were examined. The calenderability was evaluated as "good" when the film could be taken from the final roll to the take-up roll without any trouble, and "bad" when there was a problem. Further, the smoothness of the film surface was visually inspected.

The obtained film was subjected to JIS
The elongation at break of the film at a tensile speed of 200 mm / powder was determined according to K 6734. However, 100
Since 0% or more cannot be measured, it was set to 1000% or more.

(Production of a base film having an adhesive layer)
An acrylic pressure-sensitive adhesive (SK Dyne 1340, manufactured by Soken Chemical Co., Ltd.) is applied on a release paper obtained by applying a silicone-based release agent to high-quality paper so as to have a dry thickness of 30 μm, and dried to form a pressure-sensitive adhesive layer. did. After the back surface of the film obtained above was subjected to a corona discharge treatment, the release paper was adhered to the back surface to obtain a marking base film having an adhesive layer.

Using a cutting device equipped with a blade, a character having a round gothic type, a sharp cut-out portion, and a character having a size of 20 mm square is cut. The sex was "good", and when there was uncut, it was "bad".

Further, in order to evaluate the processability of attaching a base film having an adhesive layer to an adherend plate, JIS K
The 10% modulus was measured according to 6734. The 10% modulus is most preferably in the range of 1.0 to 3.0 kg / cm from the viewpoint of the workability of attaching the base film to the substrate, but is preferably in the range of 0.7 to 1.0 kg / cm or 3.0 kg / cm. ~ 7.0k
When it is in the range of g / cm, there is no problem in practical use. However, when the 10% modulus is smaller than 0.7 kg / cm or larger than 7.0 kg / cm, it is difficult to use as a marking film. Table 1 shows the above results.

Examples 2 to 4 and Comparative Examples 1 to 7 In the same manner as in Example 1, a high-density polyethylene resin
Antioxidant (Irganox 1 made by Ciba-Geigy)
076) 0.2 parts by weight and 0.2% calcium stearate lubricant
By weight, a resin composition was prepared by further adding calcium carbonate in the amount shown in Table 1 to obtain a base material film for marking having a predetermined thickness. At this time, in the same manner as in Example 1, the calenderability of the resin composition was examined, and the smoothness and elongation at break of the surface of the obtained resin film were examined.

Further, using the obtained film, a substrate film having an adhesive layer was obtained in the same manner as in Example 1.
For this, the cutting property was examined, and the workability of sticking to an adherend was examined. Table 1 shows the results.

[0044]

[Table 1]

[0045]

The marking substrate film according to the present invention is a resin composition comprising a high-density polyethylene resin having a predetermined melt flow rate and calcium carbonate having a predetermined average particle diameter mixed at a predetermined ratio. Therefore, when cutting with a blade, there is no uncut portion even at an acute angle portion such as a character or a sign, and the cutting property is excellent. According to the present invention, such a base film for marking can be obtained as a film having a smooth surface by calendering the resin composition, without being taken up in a roll, with good take-up properties from the roll. it can.

Continued on the front page F term (reference) 4F071 AA16 AA88 AB21 AD06 AE05 AE11 AG17 AH06 BB04 BC01 BC12 4F100 AA08A AK05A AT00B BA01 BA02 EJ18A GB90 JA06A JA20A YY00A 4J002 BB031 DE236

Claims (2)

[Claims] An amount of calcium carbonate having an average particle size of 0.05 to 2 μm is 3 to 30 parts by weight based on 100 parts by weight of a high-density polyethylene resin having a melt flow rate in a range of 0.03 to 1.0 g / 10 minutes. A base film for marking comprising a resin composition containing at least one part, and having a thickness in the range of 40 to 150 μm. 2. 100 parts by weight of a high-density polyethylene resin having a melt flow rate in the range of 0.03 to 1.0 g / 10 minutes, 3 to 30 parts by weight of calcium carbonate having an average particle size of 0.05 to 2 μm. A method for producing a marking base film, comprising: calendering a resin composition containing a part of the resin composition into a film having a thickness in a range of 40 to 150 μm.