JPH0418476A - Application of label - 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] [Field of Industrial Application] The present invention is applicable to containers (glass bottles, plastic moldings, etc.) for various foods, beverages, cosmetics, pharmaceuticals, chemicals, electrical products (magnetic tape cases, dry battery cases, etc.) This invention relates to a method for adhering labels to bottles, molded cases, metal cans, etc.).

[Prior Art] Currently, containers for various foods, beverages, cosmetics, pharmaceuticals, chemicals, electrical products, etc. are almost always marked with various labels.

As a method of displaying various information on various containers, various pre-printed labels (adhesive-attached paper labels,
(Pre-adhesive labels, heat-activated labels, rewetting labels, shrink sleeve labels, in-mold labels, etc.)
The methods used include fixing (fixing) the label on the container or printing it directly on the container.

There are various methods of directly printing on containers, but each method can print only the minimum necessary amount. Labels that emphasize product differentiation, cosmetics, aesthetics, etc.
It is a well-known fact that the use of pre-printed labels is common sense and widely used.

The materials of these pre-printed labels include paper-based printed labels (porous), plastic film-based printed labels, and metal foil-based printed labels (porous). It is broadly classified into non-porous type) etc.

In addition, methods for fixing these various labels to containers include applying adhesive to the back side of the label (using a labeling machine for gluing), and applying adhesive to the back of the label. You can either apply an adhesive or an activated (heat-activated, re-wet) adhesive in advance and reactivate it with heat or water before applying it to the container, or you can use an adhesive-treated label (general (called tack label) is
There are two methods: a method in which the label is pasted while peeling off the release paper, and a method in which a pre-printed plastic film is made into a sleeve (cylindrical shape) and placed over the container (shrink label).

Among these, a widely used method is to use a pre-printed label with an automatic gluing machine (labeling machine), and affix the label while applying adhesive. This method has been accepted in the market as the most economical and can process large quantities in a short time compared to other methods.

However, in a label that is attached while applying this adhesive, there is a fact that the base material on the surface to which the adhesive is applied must be made of a porous material such as paper.

This means that single-layer labels based on plastic film and laminated labels with plastic film on the adhesive side can be applied using conventional adhesives, but automatic gluing cannot be applied by a machine (labeling machine). It is impossible. Adhesives used for fixing (bonding) these adhesives include: 1) Solvent solution adhesives (natural rubber, acrylic resin, etc.)
, 2) Water-based adhesives a) Emulsion-based adhesives (vinyl acetate, ethylene-vinyl acetate copolymer, acrylic, etc.) b) Latex-based adhesives (natural rubber-based, synthetic rubber-based) C) Natural resin-based adhesives ( Casein, starch type) 3) True melt adhesive (ethylene vinyl acetate copolymer type,
thermoplastic rubber-based, acrylic-based, etc.) 4) Heat-activated adhesive (
ethylene vinyl acetate, etc.). These adhesives can be applied by applying the adhesive to the label when pasting it on the container, or by applying the adhesive to the label in advance and then adhering it with release paper, etc., if necessary. There are two methods: protect the agent layer and then peel off the release paper when pasting it on the container, or fix it (adhesion) by heat activation.

Water-based adhesives are generally used to adhere labels to porous substrates (paper, nonwoven fabrics, etc.), and most of the requirements are met. However, porous substrates have drawbacks such as the label itself having poor water resistance and the adhesive used for pasting being water-based, so the adhesive itself is not water resistant. When used in containers that are preferred to be soaked and cooled for consumption, the labels may become swollen or peel off due to water, causing problems such as making it impossible to identify the product and damaging the product's value.

In addition, since such porous substrates (paper, etc.) are inherently opaque, the markings are printed on the surface (the back side of the adhesive application side), but this printed surface is 7. Due to combing or collisions, the printed surface is often damaged or fallen off, leading to problems such as a decline in product value and legal regulation markings becoming indistinguishable and difficult for consumers to read. . This results in excessive costs for protective packaging (eg, cardboard boxes) for labeled containers.

For example, oversized packaging is required, such as packaging individual bottles (containers) in cardboard boxes and then storing them in cardboard boxes, or using paperboard partitions (referred to as partitions) inside the cardboard boxes.

In order to economically overcome the above-mentioned drawbacks of labels made of porous substrates (paper, etc.), a transparent plastic film can be used, printed on the back side of the film on the side where the adhesive is applied, and then adhesively affixed to the container. This makes it possible to prevent problems with water resistance and the printed surface from falling off or being damaged. It is considered ideal to use this plastic film (non-porous) as a label. However, it is almost impossible to do this with the label adhesives currently used for boat fishing, and the hot melt method has not yet become widespread in some areas.

Generally used adhesives for labels on porous substrates (paper, etc.) are hardly able to meet the demands for adhesion of non-porous labels, such as plastic films. This is because when a solution-type adhesive containing water or a solvent is applied to a non-porous label, that is, when the label is pasted, the solvent (water or solvent) contained in it does not volatilize or dry, and the adhesive This is not practical as it will not harden forever. Therefore, if you want to attach such a non-porous label with adhesive, you should use a true-melt solvent-free type.
Apply heat-activated adhesive to the label in advance,
The method used is to heat activate the adhesive before applying it, but since both methods use heat during adhesion, if the heating temperature is high (over 100°C), general-purpose plastic films (e.g. , ○PP, OPS, HD
Labels made of films such as PE, LDPE, and PVC have the problem of shrinking or melting due to the heat, and the container side is often distorted or warped by the heat.

In order to solve these problems, it is necessary to select materials for labels and containers that have good heat resistance, which makes them more expensive and less economical than the general-purpose plastics used for boat fishing. It will be disadvantageous.

As the base material for the label, it is a prerequisite that a general-purpose plastic film that is popular for boat fishing can be used.

Examples of general-purpose plastic films include OPP film, OPS film, HDPE film, and PVC film, but most of these films do not shrink or melt at temperatures of about 90°C to 110°C. When bonding using heat, application and activation must be completed at a temperature below this temperature range, but complete adhesion is difficult in this temperature range, so sufficient time is required to achieve this. Currently, it is not widely used because it requires a multiplication of 20% by weight, making it impossible to produce at an economical level.

For this reason, if you have given up on pasting with adhesive and absolutely require the characteristics of plastic film, the shrink label method has become common. The current mainstream labeling method is the film shrink label method, which is dividing the market into two.

This plastic film shrink label is a pre-printed heat-shrinkable plastic film that is processed into a sleeve shape (cylindrical shape), which is then placed on a container, heated, shrunk, and fixed. It is something that makes you This method is a good way to improve aesthetics and solve problems such as the printed surface falling off or being damaged, but it requires forming it into a sleeve shape in advance and covering containers with various shapes. etc., so it can be said that the labels with glue attached are very expensive compared to the labels.
The fact is that there are demands that divide the market. The many properties of this plastic film can be used at a cost similar to or lower than that of conventional porous (paper, etc.) labels, and conventional automatic gluing machines (Lahering machines) can be used as is. has been a long-held dream of this market.

The adhesive is in the form of a solution, mast, or glue, and automatic gluing can be easily applied by machine. It can be used to adhere general-purpose plastic film labels to containers, bottles, etc., and has water resistance and heat resistance. There is a desire to develop an adhesive that hardens in a short time after bonding, and many industries that require containers and bottles, such as food companies, drinking water companies, pharmaceutical companies, cosmetics companies, and electrical product companies, There is a need to supply containers and bottles that are economically coated with plastic film Rahel, which is inexpensive, aesthetically pleasing, and resistant to damage.

[Problems to be Solved by the Invention] In order to solve the above-mentioned difficulties with the conventional label bonding method, the present inventor has conducted extensive research and has discovered that a solvent-free moisture-curing adhesive can undergo moisture-curing reactions at room temperature. It can be bonded to various adherends, and after curing reaction, it has water resistance, heat resistance,
The present invention was completed by taking advantage of its excellent cold resistance.

Since the present invention does not contain organic solvents, it is safe from a sanitary and fire standpoint, and can bond to adherends that are difficult to bond with conventional adhesives. Unlike other adhesives, automatic gluing can be applied to containers and bottles by machine using a new adhesive that hardens sufficiently in a short time even when adhering materials with low air permeability. It is an object of the present invention to provide a label adhesion method capable of forming a label pasting container particularly excellent in heat resistance and cold resistance.

[Means to solve the problem]

In order to solve the above problems, in the label adhesion method of the present invention, a silicone adhesive and a modified silicone adhesive made of a polymer compound having one or more reactive silicon groups in the molecule, or A label is attached to a container using a moisture-curable adhesive selected from urethane-based adhesives made of polymeric compounds having one or more isocyanate groups.

Of course, porous labels such as paper labels can be used as the label, but the method of the present invention is also applicable to non-porous labels such as plastic labels or metal foil labels. This is a major feature.

In particular, the adhesive for labeling of the present invention includes silicone adhesives and modified silicone adhesives made of polymer compounds having one or more reactive silicon groups in the molecule, or one or more reactive silicone groups in the molecule. Moisture-curable adhesives selected from urethane adhesives made of polymeric compounds having isocyanate groups are preferably used.

Specific examples of polymer compounds having one or more reactive silicon groups in the molecule include JP-A-50-156599;
Japanese Patent Application Publication No. 52-73998, Japanese Patent Publication No. 58-1041
Compounds such as those proposed in JP-A No. 8, JP-A-62-23082, etc., and compounds that contain at least a silicon atom bonded with a hydrolyzable group as shown in JP-A-63-12677, etc. Organosilicone compounds having two or more compounds, JP-A-60-228516, JP-A-63-11
There are compositions made of an oxyalkylene polymer having a silicon group and a (meth)acrylate (co)polymer having a silicon group, as proposed in Japanese Patent Application No. 2642 and Japanese Patent Application No. 1-131271.

In particular, an acrylic acid alkyl ester monomer having (a) a reactive silicon group and whose molecular chain substantially has (1) an alkyl group having 1 to 8 carbon atoms as disclosed in JP-A-63-112642. and (2) an acrylic acid alkyl ester monomer unit and (or) a methacrylic acid alkyl ester monomer unit having an alkyl group having 10 or more carbon atoms. It is preferable to use a curable composition comprising a copolymer and (b) an oxyalkylene polymer having a reactive silicon group. Here, the reactive silicon group is a silicon-containing functional group that can be crosslinked by forming a siloxane bond, and a representative example is the general formula (I): (wherein, R1 is a substituted or unsubstituted group having 1 to 20 carbon atoms. Substituted monovalent organic group or triorganosiloxy group, X is a hydroxyl group or a different or similar hydrolyzable group, a is an integer of 0.1 or 2, b is Oll, an integer of 2 or 3 and a-2
and does not become b-3, a is an integer from 0 to 13). A preferable reactive silicon functional group from the economic point of view is represented by the general formula (II) lrl SiX, +□ (n) (wherein R' is the same as above, and n is an integer of 0, 1 or 2). This is the group that is used.

In order to make the adhesiveness of the label more effective in the present invention, the above two types of adhesives contain vinyl compounds such as vinyl chloride (co)polymer, phenolic resin compounds, coumaron indene resin, petroleum resin, and terpene. Tackifiers such as resins, terpene-phenol resins, and rosin resins, JP-A-1986
If necessary, a (meth)acrylate compound such as a pre-reacted epoxy resin or butyl acrylate (co)polymer as proposed in Japanese Patent No. 3-291918 may be added.

The adhesive that can be used in the present invention is the above compound 100
part of hardening accelerator. It is obtained by blending 1 to 10 parts.

Examples of the curing accelerator include organic tin compounds, acidic phosphoric acid esters, reaction products of acidic phosphoric acid esters and amines, saturated or unsaturated polyhydric carboxylic acids or their acid anhydrides, and organic titanate compounds. Can be mentioned.

Specific examples of the organic tin compound include dibutyltin dilaurate, dioctyltin maleate, dibutyltin naphthalate, stannous octylate, dibutyltin methoxide, dibutyltin diacetylacetonate, dibutyltin dihersate, and the like.

Examples of organic titanate compounds include titanate esters such as tetrabutyl titanate, tetraisopropyl titanate, and triethanolamine titanate.

In addition, this adhesive may contain diluents (phthalate ester plasticizers such as dioctyl phthalate and butyl hensyl phthalate, plasticizers such as epoxidized soybean oil, solvents such as methanol, ethanol, toluene, etc.) as necessary. , reactive diluents, fillers (heavy calcium carbonate, light calcium carbonate, colloidal calcium carbonate, kaolin, talc, silica, titanium oxide, aluminum silicate, magnesium oxide, zinc oxide, carbon black, etc.), adhesive agents ( Silane coupling agents such as aminosilane and epoxysilane), anti-sagging agents, colorants, preservatives, ultraviolet absorbers, light stabilizers, moisture absorbers, etc. can be added. The liquid type is easier to use, but it can be applied to both the one-component and two-component types.Adhesive can be applied to the label side, container or bottle side. can also exhibit sufficient adhesive performance.

For automatic gluing, machines (Lahering machines) that use conventional water-based adhesives, such as the LR600CR and LR306CR models manufactured by Koyo Automatic Machinery Co., Ltd., may be used, or machines similar to these Lahering machines may be used. However, there are no restrictions whatsoever. Furthermore, humidification, heating, etc. can be performed on the servicing machine, if necessary, in order to accelerate the curing of the adhesive.

The adhesive structure of the label attached to the container by the label adhesive method of the present invention is novel and unprecedented.

[Effect]

In the present invention, the affixed label actively uses moisture present in the atmosphere to improve curing failure (undrying) and water-resistant adhesion, which were major problems with water-based adhesives. Its biggest feature is that it can be applied to non-porous labels because it does not require heat for the adhesion mechanism, unlike hot-melt adhesives and heat-activated adhesives.

〔Example] Examples of the present invention will be described below.

Synthesis Examples 1 to 5 According to Synthesis Examples 1 to 5 of JP-A-63-112642, (meth)acrylic acid ester polymers as shown in Table 1 were obtained.

Table 1 Notes in Table 1 are as follows.

*l: Mitsubishi Rayon Kan O7 Crystal S *2: Mitsubishi Rayon ■ C+Z, C13 mixed alkyl methacrylate *3: γ-methacryloxypropyltrimethoxysilane *4: T-mercaptopropyltrimethoxysilane *5: Abu Bisisobutyronitrile *6: T-methacryloxypropylmethyldimethoxysilane *7: T-mercaptopropylmethyldimethoxysilane *8: Based on GPC measurement.

Synthesis Examples 6 and 7 CH at the end of the molecule according to Synthesis Examples 8 and 9 of JP-A-63-112642.

A polyoxypropylene having (CH30)2S I CHzCHtCHzO- group was obtained.

Examples 1 to 9 After blending the adhesive compositions shown in Table 2, the adhesive compositions shown in Table 2 were applied to the labels of each base material to evaluate curability, room-temperature adhesion, water-resistant adhesion, heat-resistant adhesion, cold-resistant adhesion, and various containers and bottles. The room temperature adhesion was investigated. The results are shown in Table 3 (adhesive curing properties), Table 4 (room-temperature adhesion, water-resistant adhesion, heat-resistant adhesion, and cold-resistant adhesion), and Table 5 (room-temperature adhesion to various containers and bottles).
It was shown to. In Example 2, an adhesive composition was prepared using the polymers of Synthesis Examples 2 to 5 instead of the polymer of Synthesis Example 1, and an adhesive composition was prepared using the polymer of Synthesis Example 60 instead of Synthesis Example 7. However, almost the same results as in Example 2 were obtained.

Comparative Examples 1 to 3 A vinyl acetate-acrylic (co)polymer emulsion adhesive (for labels, trade name EM-679, manufactured by Cemedine Co., Ltd.) was used as the adhesive composition, and the same tests as in the examples were conducted. The results are shown in Tables 3 to 5.

Table 2 The ingredients in Table 2 are as follows.

*l: Polymer of Synthesis Example 6.

*2: Composition of the polymer of Synthesis Example 1 and the polymer of Synthesis Example 70.

*3: Takenate LI003, trade name manufactured by Takeda Pharmaceutical Co., Ltd., polypropylene oxide type having a terminal isocyanate group *4 Nidibutyltin oxide solution, solution dissolved in equimole of dioctyl phthalate *5: N-β-(aminoethyl)amylpropyl Trimethoxysilane*6: Hakureika CCR1, manufactured by Shiraishi Calcium Co., Ltd. Product name, surface treated calcium carbonate (hereinafter referred to as the margin) Table 3 The test conditions and evaluation of the adhesive curing test shown in Table 3 are as follows.

Three types of base material labels: high-quality paper, polystyrene (product name: Styro Film 30μ, manufactured by Asahi Kasei Corporation), and polypropylene (product name: Yupo FPG 80, manufactured by Oji Yuka Synthetic Paper Co., Ltd.) are attached to bottles (glass bottles) with various adhesive compositions. After applying it using an object and then leaving it under the following three conditions,
Curing properties were evaluated.

Initial stage: Immediately after various base material labels are attached to bottles (glass bottles) (20″C165%RH).

24 hours: After attaching various base material labels to bottles (glass bottles), it is left for 24 hours at 20° C. and 165% RH.

48 hours 1 u'l: indicates 48 hours of standing at 20°C and 65% RH after attaching various base material labels to bottles (glass bottles).

Evaluation criteria for adhesive curability: O: Indicates complete curing of adhesive. If you remove the label,
Indicates material failure of the label.

Δ: The adhesive is uncured, but the label does not shift or lift up, and when the label is peeled off, the adhesive shows cohesive failure.

×: Adhesive is not cured, and label displacement and lifting are observed. If the label is removed, the adhesive dries, hardens, and exhibits cohesive failure.

In the case of Examples 1 to 3, regardless of whether the label substrate is porous or non-porous, the label using the moisture-curing adhesive has a
Completely cured in ~48 hours.

In addition, the label may shift or lift immediately after applying the adhesive,
The results were very good with no peeling.

In the case of Comparative Example 1, good results were obtained for labels made of high-quality paper, but in the case of labels made of polystyrene and polypropylene, the adhesive remained uncured even after 24 to 48 hours, and the adhesive Immediately after application, the label shifted, lifted, and peeled off, making it impossible to use these plastic labels.

Table 4 The test conditions and evaluation of the adhesive curing test shown in Table 4 are as follows.

Three types of base material labels: high-quality paper, polystyrene (trade name: Styrofilm 30μ, manufactured by Asahi Kasei Corporation), and polypropylene (trade name, Yupo FPG80, manufactured by Oji Yuka Synthetic Paper Co., Ltd.) are attached to bottles (glass bottles) with various adhesive compositions. After that, the adhesive properties of the following four types were evaluated.

a: Room temperature adhesion, adhesion after one week at 20°C, 165% RH after applying adhesive b: Water-resistant adhesion, 20°C, 165% R after applying adhesive (
After one week, immerse it in tap water at 20°C for 24 hours.
Adhesion after time C: Heat resistant adhesion, 20°C 165% RI after applying adhesive (
After one week, it was put into a hot air circulation dryer at 100"C, and the adhesiveness after 24 hours at 100°C d: Cold resistant adhesiveness, after applying the adhesive at 20°C and 165% RH. After one week, put it in a refrigerator at -20℃ and keep it at -20℃.
Adhesiveness evaluation after 24 hours under: ○: Material failure of Larabe W material (no label displacement, lifting, or peeling) O": Label base material swells with water, lifting or partial There is some peeling, but no falling off. △: There is no lifting or peeling of the Nilabel material, but it is in a state where it can be peeled off, and when it is peeled off, it shows a state of interfacial peeling from the bottle side.

× Indicates severe lifting, peeling, and falling off of the Ni label.

In the case of Examples 4 to 6, regardless of whether the label base material is porous or non-porous, the adhesiveness of the label using the moisture-curing adhesive was excellent under any of the conditions of room temperature, water resistance, heat resistance, and cold resistance. It was very good.

In the case of Comparative Example 2, the water-resistant adhesion was poor in the case of the label made of high-quality paper, but the other room-temperature, heat-resistant, and cold-resistant adhesion properties were good. On the other hand, in the case of labels made of polystyrene and polypropylene, not only the water-resistant adhesive properties were poor, but also the other room-temperature, heat-resistant, and cold-resistant adhesive properties were not good.

(Left below) Table 5 The test conditions and evaluation of the adhesion test for various container/bottle materials shown in Table 5 are as follows.

Label M material (polypropylene film, Yubo FPG80
, Oji Yuka Synthetic Paper Co., Ltd. (product name)) and applied each adhesive composition to the following various container/bottle materials.
After being left at 565% RH for one week, it was peeled off at the same temperature and its adhesion was evaluated with a valence of 81.

Glass 2 Commercially available glass plate (thickness 5 mm) Polyester: Polyester sheet (thickness 500μ) Polypropylene: Polypropylene sheet (thickness 500μ)
) Polyethylene: Polyethylene sheet (thickness 500μ) Vinyl chloride: Rigid vinyl chloride sheet (thickness 500μ) Tin plate commercially available tin plate (thickness 500μ) Adhesiveness evaluation: Material failure of O-ni label base material (label displacement, lifting, etc.) No peeling) △: Interfacial failure from the container/bottle material interface (however, there is practical strength) ×: Interfacial failure from the container/bottle material interface (however, no practical strength) In the case of Examples 7 to 9, moisture curing type Labels using adhesive showed very good adhesion to various container and bottle materials.

In the case of Comparative Example 3, the adhesion to various container/bottle materials was poor.

[Effects of the Invention] As described above, according to the present invention, ■ it is possible to attach non-porous labels to containers and bottles, which was impossible to use with conventional adhesives; ■ water resistance, heat resistance, It has excellent cold resistance; (1) it cures at room temperature, so no heating is required; and (2) it can be applied to a wide range of materials for containers and bottles.

Claims (4)

[Claims] (1) Silicone adhesives and modified silicone adhesives made of a polymer compound having one or more reactive silicon groups in the molecule, or urethane made of a polymer compound having one or more isocyanate groups in the molecule A label adhesion method characterized in that a label is affixed to a container using a moisture-curing adhesive selected from a group of adhesives. (2) The label adhesion method according to claim (1), wherein the label is a non-porous label such as a plastic label or a metal foil label. (3) A silicone adhesive and a modified silicone adhesive, which are used in the label adhesion method according to claim (1) or (2) and are made of a polymer compound having one or more reactive silicon groups in the molecule; or a moisture-curable adhesive for label bonding selected from urethane adhesives made of polymer compounds having one or more isocyanate groups in the molecule. (4) An adhesion structure for a label attached to a container by the label adhesion method according to claim (1) or (2).