JP2001279220A - Cold-seal adhesive and information carrier produced by using the adhesive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a cold-seal adhesive relieving at least one of problems of conventional cold-seal adhesive containing a natural rubber resin and further exhibiting excellent antiblocking property, cold-seal adhesivity and printability. SOLUTION: The adhesive is a water-based cold-seal adhesive containing a urethane resin (A) accounting for at least 20 wt.% of the adhesive. The urethane resin (A) is preferably produced by the polymerization of a monomer mixture having a polyol/polyisocyanate weight ratio of (1-19)/1. The urethane resin preferably has a Tg of <=50 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a
An adhesive that does not cause a tack on the coated surface where the adhesive is applied to the base sheet and the adhesive layer is formed, and the other surface where the adhesive is applied and the adhesive layer is formed Even if the coated surfaces are overlapped so that the two adhesive layers are in contact with each other, the adhesive does not cause adhesion and blocking. The present invention relates to a cold seal adhesive capable of bonding surfaces.

[0002] Further, the present invention relates to an adhesion site where such a cold seal adhesive is applied to form an adhesive layer.
In particular, regarding an information carrier having such an adhesion site, various information, for example, information requiring confidentiality, confidentiality or concealment is printed on a continuous or single-sheet base sheet, and a postcard, an envelope, or the like. , A business form, a delivery slip, a communication card, a folding card, an overlapping sheet, an information hiding sheet, and the like.

[0003]

2. Description of the Related Art In recent years, various types of information, for example, information requiring confidentiality, confidentiality or concealment, such as personal information, are printed on a continuous or single-sheet base sheet. Information carriers in the form of delivery slips, communication cards, folding cards, overlapping sheets, information concealing sheets, and the like are becoming widespread. In the present specification, the “substrate sheet” refers to a sheet-shaped substrate that is usually used for an information carrier.
Use ordinary paper, cloth, synthetic paper, or films of polyester resin, diacetate resin, triacetate resin, acrylic resin, polycarbonate resin, polyvinyl chloride resin, polyimide resin, cellophane, celluloid, etc. be able to. Furthermore, "base sheet"
Include coated paper or cast coated paper provided with a coating layer in advance, and laminated paper processed by laminating a resin film on the surface of the paper or using a molten resin.

[0004] Further, in the present specification, the term "information carrier" refers to various types of information, such as continuous (for example, continuous paper wound on a roll) or cut sheet (for example, stacked sheets). For example, information that requires confidentiality, confidentiality or concealment, such as personal information and print information, or information that does not necessarily require confidentiality, such as advertisements and advertisements, is handwritten or printed. , The medium being, for example, a postcard,
An information medium in the form of an envelope, a business form, a delivery slip, a communication card, a folding card, a superposition sheet, an information hiding sheet, or the like. An envelope or the like is not necessarily printed with information, and should be a container of information for containing an information medium. However, in this specification, the envelope is included in the information carrier described above. Furthermore, in this specification, "printing" means offset printing, gravure printing,
Alternatively, this means writing various types of information, patterns, and the like using any general printing method such as printing using a non-impact printer.

[0005] Among such information carriers, one of the most popular is a so-called confidentiality postcard. The outline of an information carrier will be described using a confidential postcard as an example. Before recording information, the base sheet used for such an information carrier is usually coated with an adhesive called a cold seal adhesive in advance on the surface to be printed of the base sheet and dried. Is formed. Next, information on the coated printing surface, for example, offset printing,
Printing is performed using a printing method such as gravure printing and printing using a non-impact printer. The order of printing and coating may be changed. Further, the printed surface on which the information is printed is overlapped so that the adhesive layer on both surfaces is in contact with the other surface on which the cold seal adhesive is applied and the adhesive layer is formed, and a certain amount or more is applied. Can be bonded by applying pressure.

[0006] Such cold seal adhesives are required to have the following basic characteristics: Under normal conditions, a tack is applied to the coated surface on which the adhesive is applied to form an adhesive layer. Does not occur; under normal conditions, adhesive coated 2
Adhesion and blocking do not occur even if the adhesive layers of the two coated surfaces are overlapped so that both adhesive layers are in contact with each other; by applying a certain pressure or more to the overlapping of the two adhesive layers Both can be bonded.

[0007] In the present specification, the "normal state" means that no special operation such as pressurizing is applied to the substrate sheet coated with the adhesive. When the coated surfaces applied to the sheets are stacked and left or stored, when the stacked base sheets are pressed strongly by hand, or when the information is printed on those coated surfaces, a low pressure (approximately 7, 7) is applied. 840 N / m ²
Pressure below).

Accordingly, in the present specification, the “cold seal adhesive” is an adhesive which does not cause tack on a coated surface on which an adhesive is applied and an adhesive layer is formed in a normal state. In a normal state, even if the adhesive layers of the two coated surfaces on which the adhesive is applied are overlapped so that the two adhesive layers are in contact with each other, the adhesive does not cause adhesion and blocking. By applying a pressure higher than the pressure at which the two adhesive layers overlap (for example, a pressure exceeding about 7,840 N / m ² and a pressure applied by a currently used mail sealer), An adhesive that can be bonded. Further, in the present specification, a property of these “cold seal adhesives” that does not adhere in a normal state but can be adhered by applying a certain pressure or more is referred to as “cold seal adhesiveness”. Further, in this specification, the force required to release the cold-sealed adhesion is referred to as “cold seal adhesion force”. still,
In the present specification, the “adhesive layer” refers to an adhesive layer after a cold seal adhesive is applied and dried.

Such a cold seal adhesive has, in addition to the above-mentioned basic characteristics, depending on the type of information carrier,
Further, various characteristics are required. When the information carrier is in the form of a confidential postcard, a communication card, a folding card, a superimposed sheet, an information concealing sheet, etc., in addition to the above basic characteristics, the cold seal adhesive has the following characteristics. Additional properties are further required: printable on the adhesive layer formed on the substrate sheet by applying the adhesive (hereinafter also referred to as "pre-coat"), or Ability to form an adhesive layer by applying an adhesive (hereinafter also referred to as “post-coating”);
In general, the bonding can be released by peeling off with a force of a person's hand to separate them from each other; the information on the surface from which the bonding has been released can be completely read, that is, the substrate is used when releasing the bonding. The sheet should not be broken (hereinafter also referred to as "removable"); the part where the bonding has been released should not be bonded again with enough pressure that a human can apply it manually.

The information carrier is a confidential postcard, a communication card,
When in the form of a folding card, an overlay sheet, an information hiding sheet, etc., the information is generally printed on a layer of adhesive formed by coating the base sheet (printing and coating). The order may be reversed). By bonding, the information is hidden. See information (know,
(Or confirm), the information is kept confidential because the adhesion cannot be achieved even if a pressure that can be manually applied by a person is applied once the adhesion is released.

On the other hand, when the information carrier is in the form of an envelope or a business form, the cold seal adhesive is required to have the following additional characteristics in addition to the above basic characteristics. To be able to release the adhesion by manually pulling the substrate sheet at the bonded position; when the adhesion is released, the substrate sheet is destroyed to the extent that it can be visually confirmed (hereinafter referred to as “material destruction”). The part where the adhesion has been released should not be adhered again even if a pressure that can be manually applied by a person is applied.

When the information carrier is in the form of an envelope, a business form, or the like, the information contained in the information carrier is different from the location where the cold seal adhesive is applied to the base sheet to form the adhesive layer. Or printed on another substrate sheet. On the other hand, the cold seal adhesive is applied to a portion to be sealed (usually called “paste”) so that information can be concealed, and a layer of the adhesive is formed. Then, the information is concealed by being sealed with a margin. Releasing the adhesion at the place where the information is adhered for viewing (knowing or confirming) the information causes breakage of the base sheet (material destruction) to the extent that it can be visually confirmed, so that the confidentiality of such information is maintained. .

When the information carrier is in the form of an envelope, a business form, or the like, the confidentiality of the information is reduced even if the information carrier is removable as in the case of the form of the confidentiality postcard. Can be kept. In this specification, a “business form” is generally a square (many rectangles)
Is folded into two or more (for example, folded into two, three, etc.) and folded, or
This refers to one in which two base sheets are superimposed on each other and the four sides are adhered to each other so that information recorded in the inside can be hidden. Business forms are, for example,
It is used in bills and bills. As the cold seal adhesive as described above, for example, Japanese Patent Application Laid-Open No. H5-25-2
The cold seal adhesive disclosed in Japanese Patent No. 95335 can be exemplified.

[0014] Such a cold seal adhesive comprises various components. As one of the components, there is a component (hereinafter referred to as "adhesive component") for imparting adhesiveness to the cold seal adhesive, and natural rubber resins (natural rubber and modified natural rubber) are mainly used. The natural rubber-based resin has an advantage that when it is used as a main component of an adhesive component in a cold seal adhesive, a cold seal adhesive having excellent cold seal adhesive strength and little tackiness can be obtained.

However, when a natural rubber resin is used as a main component of an adhesive component in a cold seal adhesive,
Since the natural rubber-based resin can be degraded by heat, light, oxygen and the like, there is a problem that the cold seal adhesive strength of the cold seal adhesive can be degraded by aging or heat and ultraviolet rays during printing. In addition, the natural rubber resin has a low mechanical stability, so that when the natural rubber resin is blended with the cold seal adhesive or when the cold seal adhesive containing the natural rubber resin is applied, the natural rubber resin is hardened. There is also a problem that the particles are easily aggregated.

In order to solve the problems of the cold seal adhesive using a natural rubber-based resin as an adhesive component, studies have been made to use a resin other than the natural rubber-based resin. As such a resin, a study on a cold seal adhesive using several synthetic resins, that is, a vinyl resin, a synthetic rubber resin, a photocurable resin, or the like as an adhesive component has been disclosed (Japanese Patent Application Laid-Open No. HEI 10-1998). -158616, JP-A-10-263466, JP-A-10-265742
And Japanese Patent Application Laid-Open No. 10-310755. However, each of these cold seal adhesives is inferior in cold seal adhesive strength and blocking resistance as compared with a cold seal adhesive using a natural rubber-based resin as an adhesive component. Therefore, a cold seal adhesive which can solve the problem of a cold seal adhesive using a natural rubber-based resin as an adhesive component has not yet been obtained yet.

[0017]

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and the problem is to solve the problem of a conventional cold seal adhesive using a natural rubber-based resin, that is, the problem of thermal adhesive. , Light, oxygen, etc., alleviate at least one problem such as the cold seal adhesive strength may be degraded, and the formation of aggregates when compounding or applying the cold seal adhesive, preferably substantially In addition, blocking resistance, cold seal adhesive strength, and printability (related to offset printing, gravure printing, printing with a non-impact printer, etc.) are good, and these characteristics can be easily adjusted appropriately. To provide a cold seal adhesive having high overall performance. Further, it is an object of the present invention to provide an adhesive site where such a cold seal adhesive is applied to form an adhesive layer. In particular, it is to provide an information carrier having such an attachment site.

[0018]

The present inventors have conducted various studies on the resin used as the adhesive component of the cold seal adhesive. As a result, as described in detail below, the adhesive component is a conventional natural rubber-based adhesive. By using a urethane resin instead of a resin, it has been found that a cold seal adhesive having good cold seal adhesive strength and blocking resistance can be obtained while at least alleviating the problems caused by using a natural rubber-based resin. Is completed.

The present inventor has studied cold seal adhesives using various synthetic resins such as synthetic rubber resins and vinyl resins as adhesive components in order to solve the above-mentioned problems. For example, JP-A-10-158616 discloses that the design of a cold seal adhesive is related to the glass transition temperature (Tg) of an acrylic resin used as an adhesive component. This is because Tg affects the tack and adhesion of the acrylic resin.

In consideration of the Tg of the resin, the use of synthetic rubber or vinyl resin having a low Tg lowers the cohesive force of the cold seal adhesive and increases the tack. Can be improved,
It has been found that blocking occurs when the base sheet coated with the cold seal adhesive is stored or when printing is performed on such a base sheet (blocking resistance is low). On the other hand, when a synthetic rubber or a vinyl resin having a high Tg is used, the result is the reverse of the above, and although the blocking resistance is improved, a problem that a sufficient cold seal adhesive force cannot be obtained has been found. Therefore, even if the present inventor designs the cold seal adhesive only by focusing on the Tg of the synthetic rubber-based resin or the vinyl-based resin, the cold seal adhesive having both good cold seal adhesive strength and good blocking resistance is obtained at the same time. Was found to be difficult to obtain.

The present inventor believes that the resin must have a low Tg in order to improve the cold seal adhesive strength, and that the cohesive strength of the resin is necessary in order to improve the blocking resistance. Thought. In other words, in order to design the intended cold seal adhesive, the Tg of the resin is low,
It was considered necessary to have a cohesive force.

The present inventors have paid attention to urethane resin as a resin having such a low Tg and high cohesive strength, and as a result of study, have been found to be equivalent to a conventionally known cold seal adhesive using a natural rubber-based resin. It has been found that a cold seal adhesive having cold seal adhesive strength and blocking resistance can be obtained, and the present invention has been completed.

The urethane resin is a multi-block copolymer comprising a hard segment comprising a repeating unit of a urethane group or a urea group and a soft segment having high flexibility. The hard segment is aggregated by having a hydrogen bond between molecular chains, and gives a strong cohesive force to the resin. On the other hand, the soft segment contains an ether group, an ester group, and a carbonate group having a very high flexibility, has a low Tg, and gives elasticity to the resin. For this reason, the urethane resin is a resin having both low Tg and high cohesive force, like the natural rubber-based resin. Therefore, like the cold seal adhesive using a natural rubber resin, the cold seal adhesive using urethane resin as the adhesive component has no tack on the adhesive surface and has excellent cold seal adhesive strength. It is believed that an agent is obtained.

According to one aspect of the present invention, there is provided a new cold seal adhesive, which is a water-type cold seal adhesive comprising a urethane resin (A) as an adhesive component. At least 2 in the total composition of the agent
A cold seal adhesive characterized in that 0% by weight is a urethane resin.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION The cold seal adhesive of the present invention is in a water form, and has a urethane resin (A) as an adhesive component.
Wherein at least 20% by weight of the total composition of the adhesive is the urethane resin (A). In the present specification, the cold seal adhesive is `` water type '', and the urethane resin contained in the cold seal adhesive, and other resins, fine particle fillers, additives, and the like, which can be included in the cold seal adhesive, are described below. In the aqueous medium, and includes a state in which these resins and the like are dissolved in the aqueous medium and / or a state in which these resins are not dissolved. In addition, throughout this specification, parts by weight and% by weight are based on a part that does not consider an aqueous medium unless otherwise specified. Therefore, the cold seal adhesive of the present invention is an adhesive in which the urethane resin (A) is at least 20% by weight of the adhesive based on the weight of the adhesive (100% by weight) without considering the aqueous medium. is there.

As used herein, the term "aqueous medium" refers to common water such as distilled water and ion-exchanged water, and is a water-soluble or water-dispersible organic solvent, and is a raw material for urethane resin. Organic solvents with poor reactivity with monomers, etc., for example,
A medium containing acetone, ethyl acetate and the like is also called an aqueous medium. The aqueous medium may further contain water-soluble or water-dispersible monomers, oligomers, prepolymers and / or other resins, and as described below, a water-type urethane resin or a water-soluble urethane resin. Emulsifier, a chain extender and / or various additives which are usually used in the production of

In the present invention, "urethane resin (A)" is a so-called urethane resin which is in a water form and has a (many) urethane bond in its main chain. There is no particular limitation as long as the agent can be obtained. The “urethane resin (A)” in a water form refers to a urethane resin present in an aqueous medium, and is in a state of being dissolved in an aqueous medium and / or not being dissolved (for example, in an emulsion form). Of urethane resin.

Such a "urethane resin (A)" is prepared by reacting a polyol having two or more hydroxyl groups in a molecule with a polyisocyanate having two or more isocyanate groups in a molecule (further, any other). May be used in combination). The urethane resin (A) has a weight ratio of polyol to polyisocyanate (polyol /
(Polyisocyanate) is preferably produced by polymerizing a monomer mixture of 1/1 to 19/1. The urethane resin (A) can be produced by using a usual method for producing a urethane resin in a water form.

The "urethane resin (A)" is, for example, a urethane resin (A) obtained by reacting a compound (M1) having two hydroxyl groups and a compound (M2) having two isocyanate groups. Can be exemplified.

Here, "a compound having two hydroxyl groups (M
"1)" is a main component constituting the main chain of the urethane resin (A), and refers to diols generally known in the urethane industry. As such diols,
For example, the following diols can be exemplified: (M1-1) one or more dicarboxylic acids such as succinic acid, glutaric acid, adipic acid, sebacic acid, azelaic acid, maleic acid, fumaric acid, phthalic acid and terephthalic acid. ,
Ethylene glycol, propylene glycol, 1,4-
Butanediol, 1,3-butanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 1,8-octanediol, 1,10-decanediol, diethylene glycol and spiro glycol Polyester diols obtained by polycondensation of at least one diol such as polyester diols, and polyester diols such as polyester diols obtained by ring-opening polymerization of lactones; (M1-2) Production of water and the above-mentioned polyester diols Diols obtained by subjecting aromatic compounds having two hydroxyl groups such as bisphenol-A, and primary or secondary amines to ring-opening addition polymerization of a cyclic ether such as ethylene oxide, propylene oxide, oxetane or tetrahydrofuran for use in , And po Lioxyethylene diol, polyoxypropylene diol, polyoxytetramethylene diol, bisphenol-A
(M1) Polyether diols such as diol obtained by ring-opening addition polymerization of propylene oxide, ethylene oxide, oxetane or tetrahydrofuran (in the case of a copolymer, any of a block copolymer and a random copolymer); -3) Polycarbonate diols.

As the above (M1), in particular, at least one of adipic acid, sebacic acid, azelaic acid and phthalic acid and ethylene glycol, propylene glycol, 3-methyl-1,5-pentanediol and neopentyl glycol, diethylene glycol , Polyester diols obtained by ring-opening polymerization of lactones, polyoxypropylene diol, polyoxytetramethylene diol, bisphenol-A with ethylene oxide, propylene oxide, oxetane Alternatively, polyether diols such as diols to which tetrahydrofuran is added, and polycarbonate diols are preferable. These (M1) can be appropriately selected according to the desired properties of the urethane resin (A), and can be used alone or in combination.

The "compound (M2) having two isocyanate groups" is a main component constituting the main chain of the urethane resin (A), and refers to diisocyanates generally known in the urethane industry. . Examples of such diisocyanates include the following diisocyanates: (M2-1) ethylene diisocyanate, 2,2,4-
Trimethylhexamethylene diisocyanate, and 1,
Aliphatic diisocyanates such as 6-hexamethylene diisocyanate; (M2-2) hydrogenated 4,4'-diphenylmethane diisocyanate, 1,4-cyclohexane diisocyanate, methylcyclohexane diisocyanate, isophorone diisocyanate, norbornane diisocyanate, and hydrogenated xylylene diisocyanate Alicyclic diisocyanates such as isocyanate; (M2-3) 1,4-phenylene diisocyanate;
Aromatic diisocyanates such as 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, 1,5-naphthalenediisocyanate, and xylylene diisocyanate.

As the above (M2), 1,6-hexamethylene diisocyanate, hydrogenated 4,4'-diphenylmethane diisocyanate, isophorone diisocyanate, norbornane diisocyanate, hydrogenated xylylene diisocyanate and the like are particularly preferable. These (M2) can be appropriately selected according to the desired properties of the urethane resin (A), and can be used alone or in combination.

Production of the urethane resin (A) obtained by reacting the compound (M1) having two hydroxyl groups and the compound (M2) having two isocyanate groups (further,
(Any other monomer may be used in combination))
The weight ratio (M1 / M2) of the compounds (M1) and (M2) used in the production of (A) is preferably from 1/1 to 19/1.

The above-mentioned urethane resin (A) can be obtained by polymerizing the above-mentioned compound by a conventional method using a solvent usually used in producing a urethane resin, using an appropriate catalyst. it can. After the polymerization, the aqueous medium can be formed by exchanging the solvent with an aqueous medium. Examples of such a production method include the synthesis of the latest urethane: formulation and functionalization / application development, edited by the Technical Information Association, section 4.25.2,
A method described in Technical Association Publishing Co., Ltd. (issued in 1989) can be exemplified. In addition, the contents of the description constitute the contents of the present specification by this citation.

Polymerization reaction conditions for the production of the urethane resin (A), such as reaction temperature, reaction time, composition and concentration of the monomer mixture in the reaction medium, reaction sequence of the monomers, type and concentration of the catalyst, and stirring speed. Can be appropriately selected depending on the properties of (A) and the like.

The "solvent" used in the production of the urethane resin (A) is not particularly limited as long as it is a solvent generally used in the urethane industry, and further includes a raw material, a urethane prepolymer and a urethane resin to be formed. Particularly preferred is an organic solvent that dissolves (A), for example, N
Amides such as methylpyrrolidone, dimethylformamide, and dimethylacetamide; ketones such as acetone and methylethylketone; esters such as ethyl acetate and isopropyl acetate; and other cellosolve acetate and cellosolve ether.

The "catalyst" used in the production of the urethane resin (A) is not particularly limited as long as it can be used in the production of the urethane, but a polymerization catalyst known in the urethane industry can be used. For example, [2,2,2] diazabicyclooctane (DABC
O), tertiary amines such as tetramethylenediamine, N-methylmorpholine, and diazabicycloundecene (DBU), and dibutyltin (tin) dilaurate (D
Organic metals such as BTDL) can be exemplified.

Further, in order to improve the stability of the urethane resin (A) in the water form (dispersion stability of the resin in the aqueous medium and / or prevention of phase separation), it is usually used for the production of the urethane resin in the water form. Can be used. That is, a method of imparting hydrophilicity to the urethane resin itself by introducing a hydrophilic functional group into the skeleton of the urethane resin to improve the dispersion stability of the urethane resin itself in an aqueous medium and to prevent phase separation (hereinafter, referred to as a method) Emulsifier (surfactant) used in the production of urethane resin in water form or "self-emulsification"
(Hereinafter, also referred to as “forced emulsification”) can be used. These methods can be used alone or in combination.

In order to introduce a hydrophilic functional group into the skeleton of the urethane resin, the compound (M3) which introduces a hydrophilic functional group into the skeleton of the urethane resin is used for the production of the urethane resin (A). Can be. This (M3) is a compound used for the purpose of improving the stability of the urethane resin (A) in the water form by self-emulsification, and comprises a functional group containing at least one active hydrogen and a hydrophilic functional group. It is a compound having a group (hydrophilic group).

Here, the “functional group containing active hydrogen” means
Functional group containing hydrogen reactive with the isocyanate group, for example, a hydroxyl group (-OH), amino group (-NH _2, -NH
-), Mercapto group (-SH), carboxyl group (-C
OOH), amide group (-NHCO-), urea group (NH
CONH-) and a urethane group (-NHCOO-). As the functional group containing active hydrogen, a hydroxyl group, an amino group, and a mercapto group are particularly preferable.

Examples of such a “compound (M3) for introducing a hydrophilic functional group into the urethane skeleton” include the following compounds: (M3-1) N-methyldiethanolamine and N-methyldiethanolamine
Compounds having one or more active hydrogen-containing functional groups and cationic hydrophilic groups such as butyldiethanolamine; (M3-2) dihydroxylcarboxylic acids such as dimethylolpropionic acid and dimethylolbutanoic acid, 1-carboxy-1 Compounds having a functional group containing at least one active hydrogen and an anionic hydrophilic group, such as diaminocarboxylic acids such as 1,5-diaminopentane, dihydroxysulfonic acids, and diaminosulfonic acids; (M3-3) polyethylene glycol and polyethylene Compounds having a functional group containing at least one active hydrogen and a nonionic hydrophilic group, such as a block copolymer of glycol and polypropylene glycol.

As the above (M3), compounds having a functional group containing at least one active hydrogen and a nonionic hydrophilic group, such as dimethylolpropionic acid and dimethylolbutanoic acid, are particularly preferable. These (M3) can be appropriately selected depending on the properties of the urethane resin (A), and are reacted alone or in combination with the above (M1) and (M2) to give the urethane resin a hydrophilic structure. (A) into which the functional group (1) has been introduced.

(M3) is preferably used in an amount of 1 to 20 parts by weight, based on 100 parts by weight of the whole monomer composed of (M1) and (M2) used in the production of the urethane resin (A). , More preferably 1 to 15 parts by weight, particularly preferably 1 to 10 parts by weight.

The "emulsifier" used for the forced emulsification in the production of the urethane resin (A) is preferably an emulsifier which does not adversely affect the polymerization reaction and the properties of the obtained (A).
As such an "emulsifier", a mixture selected from the group consisting of compounds having a sulfonic acid group, a sulfonate group, a sulfate group, a polyoxyethylene group and the like, and a mixture thereof can be used. In addition, ordinary surfactants can also be used, for example, soaps, alkyl sulfonates, and anionic surfactants such as polyoxyethylene alkyl sulfates, polyoxyalkyl aryl ethers and oxyethylene oxypropylene blocks. Nonionic surfactants such as copolymers can be exemplified.

Further, in producing the urethane resin (A),
A chain extender (M4) generally used in the production of a normal urethane resin can be used. Examples of such “chain extender (M4)” include the following compounds: (M4-1) ethylene glycol, propylene glycol, 1,4-butanediol, 1,3-butanediol, 3- Methyl-1,5-pentanediol, 1,6-
Diols such as hexanediol, neopentyl glycol and diethylene glycol; (M4-2) ethylenediamine, propylenediamine,
Diamines such as butylenediamine, hexamethylenediamine, piperazine, isophoronediamine, tolylenediamine, xylylenediamine, and iminobispropylamine. These (M4) can be reacted with (M1), (M2), and (M3) described above. These (M
4) can be appropriately selected according to the properties of the urethane resin (A), and can be used alone or in combination.

These chain extenders (M4) are used in the production of the above-mentioned urethane resin (A) (M1), (M4)
It is preferably used in an amount of 1 to 20 parts by weight, more preferably 1 to 15 parts by weight, particularly preferably 1 to 10 parts by weight, per 100 parts by weight of the whole compound of 2) and (M3). . With respect to the urethane resin (A), the compounds (M3) and (M4) are reacted with the compounds (M1) and (M2) to produce a urethane prepolymer that forms the skeleton of the urethane resin. It is preferred to react.

In the present invention, the urethane resin (A) is
As described below, it preferably has certain properties. First, the above (M1) used when producing the urethane resin (A) is preferably 50 to 98% by weight, and preferably 55 to 98% by weight, assuming that the whole raw material used for producing (A) is 100% by weight. 95% by weight is particularly preferred. If the (M1) content of the urethane resin (A) is less than 50% by weight, the urethane resin becomes hard and the cold seal adhesiveness is undesirably reduced.

Further, the glass transition temperature (T
g) is preferably at most 50 ° C, more preferably at most 40 ° C, particularly preferably at most 30 ° C. Tg of urethane resin
If the temperature exceeds 50 ° C., the resin becomes hard and the cold seal adhesiveness decreases, which is not preferable.

The term "Tg of urethane resin" used herein refers to the measurement of viscoelasticity of urethane resin using DVE4 (trade name) manufactured by Rheometrics Co., Ltd. The stress is measured, and the tangent of the phase difference δ between the obtained stress and the applied strain, that is, tan δ is defined as the temperature at which the peak top is provided. Therefore, a curve of tan δ with respect to temperature is obtained from the value of δ with respect to temperature measured in the measurement of the viscoelasticity of the urethane resin, and the temperature at which the peak top of the curve is given is defined as Tg of the urethane resin.

Further, the average particle size of the urethane resin (A) is preferably from 0.1 to 10 μm, more preferably from 0.5 to 5 μm. Here, the “average particle diameter of the urethane resin (A)” refers to a particle diameter measured by a light scattering method.

As such a urethane resin, a commercially available urethane resin can be used.
For example, Luphen D259U (trade name) manufactured by BASF, Disperco manufactured by Sumitomo Bayer Urethane Co., Ltd.
11 U42 (trade name) and the like. The urethane resin (A) can be used alone or in combination.

In the cold seal adhesive of the present invention, at least 20% by weight of the entire adhesive is a urethane resin (A). Further, in the cold seal adhesive of the present invention, it is more preferable that 25% by weight or more of the entire adhesive is the urethane resin (A), and that 30% by weight or more of the entire adhesive is the urethane resin (A). Particularly preferred. Urethane resin (A)
If the content is less than 20% by weight of the whole adhesive, there arises a problem that cold seal adhesiveness is not exhibited. Here, “% by weight” is based on a (dry) state not containing an aqueous medium, as described above.

The cold seal adhesive of the present invention preferably further comprises a polyolefin resin (B). Here, the “polyolefin resin (B)” is used in the cold seal adhesive of the present invention for the purpose of imparting abrasion resistance, blocking resistance, and removability, and is generally used. The cold seal adhesive of the present invention is not particularly limited as long as it can be a polyolefin-based resin, which can be in a water form, and does not adversely affect the cold seal adhesive of the present invention. The “polyolefin-based resin (B)” which is in a water form refers to a polyolefin-based resin present in an aqueous medium, and is a polyolefin-based resin dissolved in an aqueous medium and / or not dissolved (for example, And polyolefin-based resins (in emulsion form).

As such a polyolefin resin (B), for example, polyethylene, polypropylene and halogenated polyolefin such as chlorinated polyethylene and chlorinated polypropylene are modified (for example, carboxyl group, sulfonic group, phosphoric acid group). Modified with a hydrophilic group such as a group, a hydroxyl group, or an amino group), a resin that can be present in an aqueous medium by using an emulsifier or a water-soluble polymer, and an aqueous resin. The above-mentioned resin dispersed in a medium can be exemplified. As the polyolefin resin (B), an aqueous dispersion of polyethylene is particularly preferable. Such a polyolefin-based resin (B) can be produced by a known method, but a commercially available resin can be used, and for example, Chemipearl W308 (trade name) manufactured by Mitsui Chemicals, Inc. can be exemplified.

The softening point of the polyolefin resin (B) is as follows:
40 ° C. or higher is preferable, 70 ° C. or higher is more preferable, and 1
A temperature of at least 00 ° C. is particularly preferred. Here, the “softening point of the polyolefin-based resin (B)” refers to a softening point measured using a ring and ball method softening point test shown in JIS K2207.

The average particle size of the polyolefin resin (B) is preferably 0.1 to 20 μm, and 0.5 to 15 μm.
It is particularly preferred that it is μm. Here, the “average particle diameter of the polyolefin-based resin (B)” refers to a particle diameter measured by a Coulter counter method. The polyolefin-based resin (B) can be used alone or in combination. The cold seal adhesive of the present invention is a polyolefin resin (B) with the total adhesive being 100% by weight.
Is preferably contained in an amount of 0 to 30% by weight, particularly preferably 3 to 25% by weight.

The cold seal adhesive of the present invention preferably further comprises a polyamide resin (C).
Here, the “polyamide resin (C)” is used in the cold seal adhesive of the present invention for the purpose of imparting wear resistance, blocking resistance, and removability, and is generally used. The polyamide-based resin used may be a water-based resin, and is not particularly limited as long as it does not adversely affect the cold seal adhesive of the present invention. The “polyamide-based resin (C)” which is in a water form refers to a polyamide-based resin present in an aqueous medium, and a polyamide-based resin dissolved in an aqueous medium and / or not dissolved (for example, , An emulsion form).

As such a polyamide resin (C), for example, a polycondensate of a diamine and a dicarboxylic acid is modified (for example, a carboxyl group, a sulfonic acid group,
A resin that can be present in an aqueous medium by denaturing with a hydrophilic group such as a phosphate group, a hydroxyl group, or an amino group), a resin that can be present in an aqueous medium by using an emulsifier or a water-soluble polymer, In addition, the above-mentioned resins and the like dispersed in an aqueous medium can be exemplified. As the polyamide resin (C), an aqueous dispersion of polyamide is particularly preferable. Such a polyamide resin (C) can be produced by a known method, but a commercially available one can be used. For example, Micromid 144LT manufactured by Arizona Chemical Co., Ltd.
L (product name) can be exemplified.

The polyamide resin (C) can be used alone or in combination. The cold seal adhesive of the present invention preferably contains the polyamide resin (C) in an amount of 0 to 30% by weight, and particularly preferably 3 to 25% by weight, based on 100% by weight of the entire adhesive.

In the cold seal adhesive of the present invention, a resin other than (A), (B) and (C),
At least one kind of resin having a Tg of -30 ° C or higher (D)
Is preferably further comprised. In the present invention, “a resin other than (A), (B) and (C),
g is at least one resin (D) having a temperature of -30 ° C or higher ”
Is a compound that is added to the cold seal adhesive of the present invention for the purpose of imparting blocking resistance, adhesion to a base sheet, and abrasion resistance.
A resin other than (B) and (C), wherein Tg is -30.
At least one kind of resin (hereinafter, also referred to as “resin (D)”) generally used for cold seal adhesives at a temperature of not less than ° C. may be used. The resin (D) is not particularly limited as long as it can be in a water form and does not adversely affect the cold seal adhesive of the present invention. In addition, the "resin (D)" which becomes a water form is the resin (D) which exists in an aqueous medium.
And includes the resin (D) in a state of being dissolved in an aqueous medium and / or the resin (D) in a state of not being dissolved (for example, an emulsion form or a latex form).

Examples of such a resin (D) include vinyl resins, synthetic rubber resins, and water-soluble polymers. Here, the “vinyl resin” is a polymer formed by addition polymerization of a vinyl compound, and includes, for example, vinyl acetate, styrene, ethylene, (meth) acrylic acid, (meth) acrylates, acrylonitrile, A polymer obtained by addition polymerization of acrylamide alone or in combination can be exemplified.

Examples of the "synthetic rubber resin" include styrene-butadiene copolymer (SBR), acrylonitrile-butadiene copolymer (NBR), and copolymers of acrylic esters and butadiene (MBR). Examples of the “water-soluble polymer” include starch, casein, cellulose, polyvinyl alcohol, and modified products thereof (for example, cation-modified products, acid-modified products, and silane-modified products).

Such a resin (D) can be produced by a known method, but a commercially available resin can be used. For example, as a synthetic rubber resin, Nipol manufactured by Nippon Zeon Co., Ltd.
LX416 (trade name) and Nipol SX1706 (trade name) manufactured by Zeon Corporation as vinyl resin can be exemplified.

The Tg of the resin (D) is -30 ° C. or higher, and particularly preferably -20 ° C. or higher. Here, the resin (D)
The Tg in the above refers to a temperature described below measured using a differential scanning calorimeter (DSC). Using DSC, the heat capacity of the resin (D) is measured to obtain a DSC curve. The DSC curve drawn at the point where the slope of the DSC curve of the step change portion based on the glass transition becomes the maximum, and the straight line obtained by extending the low temperature side baseline of the step change portion based on the glass transition to the high temperature side of the DSC curve. The temperature at the intersection with the tangent to the curve is defined as Tg of the resin (D).

The resin (D) is preferably in the form of an emulsion, but may be dissolved in an aqueous medium. Resin (D)
Can be used alone or in combination. The cold seal adhesive of the present invention preferably contains the resin (D) in an amount of 0 to 80% by weight, and particularly preferably contains the resin (D) in an amount of 1 to 60% by weight, based on 100% by weight of the whole adhesive.

The cold seal adhesive of the present invention may further comprise a fine particle filler. Here, the "fine particle filler" is a fine particle filler usually used in cold seal adhesives, for example, silica gel, hollow silica, mica, calcium carbonate, kaolin, talc, diatomaceous earth, urea resin, styrene Examples include beads, clay, cereal starch, and modified starch. Also,
The fine particle filler is usually a particle, and its size is not particularly limited as long as the desired performance of the present invention is exhibited. These fine particle fillers can be used singly or in combination, appropriately selected according to the required properties. By using a fine particle filler, it is possible to easily and suitably adjust properties such as cold seal adhesive strength, blocking resistance, printability, abrasion resistance, and adhesion to a base sheet required as a cold seal adhesive. Can be.

In the present invention, various additives can be added to the cold seal adhesive. Here, the "additive" is an additive usually used as necessary in a cold seal adhesive, for example, a lubricant, a printability improver, an antioxidant, an ultraviolet absorber, a radical scavenger,
Examples include a conductive agent, a fluorescent paint, a coloring dye, a stabilizer, an antifoaming agent, a fungicide, a bactericide, a thickener, and a humectant.

Further, in the present invention, a tackifier such as rosin can be added in order to improve the cold seal adhesive strength of the cold seal adhesive.
These additives can be used singly or in combination, and can be appropriately selected and used according to the required properties. By using these additives, a cold seal excellent in printability, stability, and antifungal properties can be obtained. An adhesive can be provided.

As described above, the cold seal adhesive of the present invention contains at least 20% by weight of the entire adhesive, the urethane resin (A), and if necessary, the polyolefin resin (B) and the polyamide resin. (C), a resin (D), a fine particle filler, and the like, which are in a water form. Further, in the cold seal adhesive of the present invention, the urethane resin (A) and the polyolefin-based resin (B), the polyamide-based resin (C), and the resin (D), which are added as needed, are present in an aqueous medium. And a form in which they are dispersed in an aqueous medium is particularly preferable. In order to maintain this form and develop appropriate cold seal adhesion, an aqueous medium can be appropriately added to produce, store and use.

Therefore, the cold seal adhesive of the present invention does not use a natural rubber-based resin as an adhesive component.
It alleviates the problems associated with cold seal adhesives using natural rubber-based resins as the adhesive component, and can preferably be substantially eliminated, and at least 20% of the total adhesive
Since it contains the urethane resin (A) by weight%, it can exhibit excellent performance in cold seal adhesive strength and blocking resistance.

The cold seal adhesive of the present invention is suitable as an adhesive for bonding a base sheet by applying pressure. The present invention further provides an adhesion site in which the above cold seal adhesive is applied to a base sheet and dried to form an adhesive layer. In the present specification, "adhesion site"
The term refers to a portion where a cold seal adhesive is applied and dried to form an adhesive layer, but is not yet bonded by applying pressure.

In one embodiment of the invention, a cold seal adhesive is applied to the surface of the substrate sheet to be printed and dried to form an adhesive layer, and the information is printed on the surface to be printed. Then, a part of the printed surface and the other part are folded so as to be in contact with each other, and the folded adhesive layers are overlapped so as to be in contact with each other, thereby providing an adhesive portion for crimping the two together.

In another embodiment of the present invention, a cold seal adhesive is applied to the surface of the base sheet to be printed and dried to form an adhesive layer, and the information is printed on the surface to be printed. Then, the printed surface is coated with a cold seal adhesive and dried so that the other surface on which the adhesive layer is formed and the adhesive layer on both surfaces are in contact with each other. Provides an adhesive site for crimping.

In a preferred embodiment of the present invention, a cold seal adhesive is applied to a portion of the base sheet where no information is to be printed and which should be sealed so that the information can be concealed, and dried to form an adhesive layer. After forming, the part of the coated part and the other part are folded so that they are in contact with each other, and the folded adhesive layers are overlapped so that they are in contact with each other, and the two parts are bonded together so that the two parts are pressed together. Provide the site.

In another preferred embodiment of the present invention, a cold seal adhesive is applied to a portion of the base sheet where no information is to be printed and which should be sealed so that the information can be concealed, dried and dried. After forming the layer, the cold-seal adhesive is applied to the applied portion and the portion to be sealed so that the information on the other surface can be concealed, and the portion where the adhesive layer is formed by drying. It is superimposed on each other to provide an adhesive site for crimping the two together.

In the present specification, the “base sheet” is as described above. Here, in the present specification, “another surface on which a cold seal adhesive is applied (dried) to form an adhesive layer” means “the cold seal adhesive of the present invention is applied, And) any other surface on which the layer of adhesive is formed (usually the surface of the base sheet), for example such a surface may be printed before coating, or It may be printed on the adhesive layer formed by coating. Specifically, it refers to a surface that has been subjected to coating → printing, printing → coating, or only coating.

In the present specification, “coating” can be used without any limitation as long as it is a coating method conventionally used as a method for applying a cold seal adhesive. For example, a roll coater, a bar coater, a blade coater, an air knife coater, a rod blade coater, a gravure roll coater and the like can be exemplified. Further, the “coating” includes a method used for applying a cold seal adhesive, and for example, coating and spraying can be used.

Further, in this specification, the term “drying” is used without limitation as long as it is a drying method conventionally used as a drying method for removing an aqueous medium from a cold seal adhesive. can do. For example, warm-air drying, reduced-pressure drying, high-frequency drying, and natural drying can be exemplified.

Further, the term “pressure bonding” refers to a method in which an adhesive is applied and dried to form two layers of an adhesive in contact with each other in a manner similar to the processing conventionally used for cold sealing. And applying pressure and, if necessary, heat as necessary to bond the two surfaces together. Therefore, "crimping"
It also means that pressure is applied to the bonding portion of the base sheet to bond it integrally.

Further, "a place to be sealed so that information can be concealed" is a place to be coated with an adhesive provided on a base sheet in order to form an information carrier and seal it. This usually refers to a place called "paste" and usually refers to a place to be sealed with a pressure-sensitive adhesive. This “place that must be sealed to hide information”
This will be further described later in a specific form (envelope and business form).

Further, the present invention provides the above-mentioned bonding site bonded by applying pressure. Therefore, the above-mentioned bonded portion bonded is also included in the present invention.

In the case where the bonding of the bonding portion is released after the bonding portion of the base sheet is pressed, the above two types of bonding can be released, that is, “removable” and “material destruction” can be obtained. . In the present specification, "removable" means that the two surfaces, which have been concealed by crimping them together as described above, can be easily peeled off by hand, and the recorded information can be completely identified. That means. Further, in this specification, "material destruction" means that the two surfaces, which have been concealed information by pressing together as described above, can be easily peeled off by hand, and at that time, the base sheet is broken, It means that traces that can be confirmed can be recognized.

In the above-mentioned embodiments of the two bonding sites, the bonded sites can be re-peeled. However, after the pressure bonding, the information is viewed again (known or confirmed). Preferred). In contrast,
In the latter two bonding sites, the bonded site is more preferably a material break, but may be removable. In the present invention, the removability of the bonded portion and the material destruction can be appropriately selected by controlling various conditions such as the composition of the cold seal adhesive and the magnitude of the applied pressure.

The cold seal adhesive of the present invention can be used by using the same method as that of a conventionally used cold seal adhesive. Can be. Therefore, the present invention uses a cold seal adhesive containing at least 20% by weight or more of the urethane resin (A) based on the whole adhesive, and thus, uses a cold seal adhesive containing a natural rubber-based resin as an adhesive component. The present invention provides an adhesive site which alleviates the problem, is preferably substantially eliminated, and exhibits excellent performance in adhesiveness and blocking resistance.

Further, an information carrier having such an adhesion site is provided. Particularly preferred as such information carriers are confidential postcards, envelopes, and business forms. However, here, the base sheet used for the information carrier, the conditions for applying the cold seal adhesive, the thickness of the adhesive layer provided on the base sheet, and the crimping conditions for the information carrier are as follows:
The intended information carrier (including removable or material destruction)
Is appropriately selected according to the conditions.

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings. FIG.
Is an illustration of a bi-fold confidentiality postcard. FIG. 2 is an explanatory diagram of an envelope. FIG. 3 is an explanatory diagram of a half-fold business form. FIG. 4 is an explanatory diagram of a two-sheet business form.

First, the case where the information carrier is in the form of a confidential postcard will be described. In FIG. 1, a cold seal adhesive is applied to one surface of one base sheet 1 and dried to form an adhesive layer. Get. The base sheet 1 is bent along a dashed line so that the adhesive layers at the bonding portions 2 overlap each other. Thereafter, pressure is applied to the overlapping bonding portions 2 to bond the bonding portions 2 to each other, thereby obtaining the intended two-fold compliant postcard 3. still,
The bonding portion 2 is the entire portion where the cold seal adhesive is applied and dried to form an adhesive layer in all of the following embodiments. It should be noted that a tri-fold confidentiality postcard can be obtained by using the same method.

When the information carrier is in the form of a confidential postcard, the base sheet is preferably regular paper, coated paper, or cast-coated paper. Further, after printing the information on the adhesive layer formed by applying and drying the cold seal adhesive of the base sheet, the adhesive portion may be pressed or bonded (also referred to as “first coating”). ) Or printing information on the base sheet, applying a cold seal adhesive on the information to form an adhesive layer, and then pressing the adhesive portion (also referred to as “post-coating”). ). In both cases of pre-coating and post-coating, the bonding site has information. Then, by compressing the adhesive portion having such information, a confidential postcard in which the information is hidden can be formed.

In the case where the information carrier is in the form of a confidential postcard, it is preferable that the adhesion of the bonded bonding portion can be released again. The composition of the cold seal adhesive in this case is such that it does not cause tack under normal conditions, does not adhere or block, cold seal adhesiveness, cold seal adhesive strength, printable on the adhesive layer, and re-peelable, etc. Is preferably determined in consideration of the characteristics described above.

In the case where the release of the bonded portion at the press-bonded portion is releasable, a preferable composition of the cold seal adhesive is 100% by weight of the entire adhesive.
Examples are urethane resin (A): 30 to 60% by weight, olefin-based resin (B): 0 to 20% by weight, resin (D): 0 to 20% by weight, and fine particle filler: 0 to 50% by weight. Here, as a preferable pressure used for pressure bonding, a surface pressure of 1,000,000 N / m ² or more 50,000
It can be, for example, not more than 000 N / m ² .

Next, the case where the information carrier is in the form of an envelope will be described. In FIG. 2, a cold seal adhesive is applied to a portion of the envelope made of the base sheet 1 which should be sealed by applying a normal pressure-sensitive adhesive, dried, and an adhesive layer is formed to adhere. Obtain site 2. The sheet is folded along the alternate long and short dash line so that the layers of the adhesive at the bonding portion 2 overlap each other. Thereafter, pressure is applied to the bonding portion 2 to bond the bonding portion 2 to obtain the desired envelope 4.

Therefore, it can be easily understood that the “location to be concealed so that information can be concealed” in the present specification is a location to seal the envelope, that is, a so-called “paste”. When the envelope is sealed, the information inside the envelope can be hidden. When the information carrier is in the form of an envelope, the “paste” corresponds to the bonding portion. still,
The information concealed by the envelope may be printed directly on the inside of the envelope (base sheet), or on another sheet (paper).
Etc. and put in an envelope.

When the information carrier is in the form of an envelope, the base sheet is preferably ordinary paper, coated paper, or cast-coated paper. In addition, the release of the bonded bonding portion may be re-peelable or material destruction. In the case where the adhesion of the pressure-bonded bonding portion can be removed again, the composition of the cold seal adhesive used in the form of an envelope, the pressure bonding conditions, and the like are the same as in the case where the information carrier is in the form of a confidential postcard. On the other hand, when the release of the pressure-bonded adhesive part is material destruction, the composition of the cold seal adhesive does not cause tack in a normal state, does not adhere or block, cold seal adhesiveness, cold seal adhesive strength. It is preferably determined in consideration of characteristics such as material destruction and the like.

In the case where the release of the bonded portion at the press-bonded portion is material destruction, as a preferable composition of the cold seal adhesive, if the whole adhesive is 100% by weight, for example, urethane resin (A): 65 to 90% by weight And polyamide-based resin (C): 0 to 30% by weight, resin (D): 0 to 35% by weight, and fine particle filler: 0 to 30% by weight.
Here, the pressure used for the pressure bonding is a surface pressure of 7,840.
A pressure exceeding N / m ² (pressure applied in a normal state) is preferable, and 100,000 N / m ² or more and 50,000,
000 N / m ² or less is more preferable.

Further, a case where the information carrier is in the form of a business form will be described. In FIG. 3, the area to be sealed by applying a pressure-sensitive adhesive around one surface of one base sheet 1 is usually a band of several cm from the end of the four sides. Here, the cold seal adhesive is applied. Coating and drying to form an adhesive layer to obtain the bonding site 2. The sheet is folded along the alternate long and short dash line so that the layers of the adhesive at the bonding portion 2 overlap each other. Thereafter, pressure is applied to the bonding site 2 to bond the bonding site 2 to obtain the desired two-fold business form 5. Note that a tri-fold business form can be obtained using the same method.

In FIG. 4, two base sheets 1
The area to be sealed by applying a pressure-sensitive adhesive around one side of is usually in the form of a band several centimeters from the edges of the four sides,
Here, a cold seal adhesive is applied and dried to form an adhesive layer to obtain an adhesive portion 2. The two layers of the adhesive at the bonding portion 2 are overlapped with each other so as to be in contact with each other. Thereafter, pressure is applied to the bonding site 2 to bond the bonding site 2 to obtain the desired two-ply business form 6.

[0098] In this form of business form, "a place to be sealed so that information can be concealed" in this specification
It can be easily understood that “is a place where the business form is sealed, that is, a so-called“ paste ”. The business form hides information inside the business form by sealing. The information hidden by the business form is usually printed directly on the inside of the envelope.

When the information carrier is in the form of a business sheet, the base sheet is preferably ordinary paper, coated paper, or cast-coated paper. When releasing the adhesion of the crimped adhesive part of the business form and looking at the information inside, considering that the information is not printed at the adhered part,
As in the case where the above-described cold seal adhesive is used for an envelope, any of re-peelable and material destruction can be used to release the adhesion of the bonded bonding portion. The composition of the cold seal adhesive and the conditions for pressure bonding in the case of removability are the same as those described in the case of the form of a confidential postcard. The composition of the cold seal adhesive and the conditions for pressure bonding in the case of material destruction are the same as those described for the case of the envelope.

[0100]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to working examples and comparative examples. However, these examples are merely one embodiment of the present invention, and the present invention is not limited to these examples. Absent. In the description of the examples, unless otherwise specified, the parts not considering the aqueous medium are based on parts by weight and% by weight.

Examples 1 to 5 show examples of the cold seal adhesive which can release the adhesion of the press-bonded adhesion portion again. Example 1 (1) Production of urethane resin of Example 1 After the inside of a reaction vessel equipped with a stirrer, a thermometer, a nitrogen inlet tube, and a reflux condenser was replaced with nitrogen gas, isophorone diisocyanate (IPDI) was used. 175 g, 550 g of polypropylene glycol (PPG, molecular weight 2000),
And 32 g of dimethylolpropionic acid (DMPA), 140 g of ethyl acetate as an organic solvent and 0.04 g of dibutyltin laurate (DBTDL) as a catalyst were added, and the mixture was heated and reacted at 80 ° C. for 6 hours under a nitrogen atmosphere. A mixture containing a urethane prepolymer in which isocyanate groups remained was obtained.

The mixture containing the urethane prepolymer was cooled to 50 ° C., and 1500 g of distilled water containing 20 g of triethylamine and 27 g of piperazine hexahydrate was added thereto under high-speed stirring to disperse the mixture. The mixture was further stirred at 50 ° C. for 3 hours. A chain lengthening reaction was performed to increase the molecular weight. Ethyl acetate was recovered from the resulting mixture to obtain a water-based urethane resin substantially free of an organic solvent.

Incidentally, the weight ratio of polyol to polyisocyanate (polyol / polyisocyanate) in producing this urethane resin is 3.14 / 1. The Tg of the urethane resin is -50C. Here, "Tg of urethane resin" was measured as follows. That is, the viscoelasticity of the urethane resin was measured using DVE4 (trade name) manufactured by Rheometrics Co., Ltd., and the stress with respect to the strain applied to the urethane resin at a frequency of 1 Hz was measured in the shear mode. This was repeated at various temperatures. The tangent of the phase difference δ between the obtained stress and the applied strain, that is, tan δ is plotted against the measured temperature, and the temperature at which the peak top of the curve is given is the T of the urethane resin.
g.

(2) Production of Cold Seal Adhesive of Example 1 As the urethane resin (A), 100 parts by weight of the urethane resin of Example 1 described above, and as the polyolefin resin (B), the softening point was 132 ° C. Low molecular weight polyolefin having an average particle size of 7 μm (this polyolefin is in the form of an emulsion): 30 parts by weight, as resin (D), SBR having a Tg of the resin of 23 ° C. and an average particle size of 0.1 μm
(However, this SBR is in latex form): 30 parts by weight and calcined kaolin (manufactured by Takehara Chemical Industry Co., Ltd., Gromax LL (trade name)): 60 parts by weight. Was obtained as a cold seal adhesive.

Here, the softening point of the polyolefin resin (B) was determined by using a ring and ball method softening point test described in JIS K2207. Furthermore, polyolefin resin (B)
The average particle size of was measured using a Coulter counter method. The Tg of the resin (D) was measured using a differential scanning calorimeter. The heat capacity of the resin (D) was measured using DSC to obtain a DSC curve. A DS drawn at a point where the slope of the DSC curve of the step change portion based on the glass transition is maximized and a straight line obtained by extending the low temperature side baseline of the step change portion based on the glass transition of the DSC curve to the high temperature side.
The temperature at the point of intersection with the tangent to the C curve was determined, and this was used as the resin (D)
Of Tg. Furthermore, the average particle size of the resin (D) is
It was measured using the light scattering method.

(3) Evaluation of Cold Seal Adhesive of Example 1 (i) Preparation of Coated Sheet A high quality paper having a basis weight of 90 g / m ² was used as a base sheet.
One side of this high quality paper has a dry weight of 8 g / m ² ,
The cold seal adhesive of Example 1 was applied and dried to obtain a coated sheet having an adhesive layer formed thereon (hereinafter also referred to as “coated sheet of Example 1”).

(Ii) Evaluation of Cold Seal Adhesion After the coated sheet of Example 1 was pressed, the adhesive force at the time of peeling was measured to evaluate the cold seal adhesion. The coated sheet of Example 1 was folded in two so that the adhesive layers were overlapped, and pressure-bonded using a mail sealer for pressure bonding while changing the gap between the rollers in various ways. After leaving the press-coated coated sheet for 30 minutes, a tensile tester (Tensilon, manufactured by Orientec Co., Ltd.) was used.
A T-peel test was performed at a pulling speed of m / min, and the force required for peeling (this is the cold seal adhesive strength) was measured. When a cold seal adhesive force of 10 N / m or more can be obtained by changing the gap between the rollers and press-bonding, the cold seal adhesiveness is evaluated as ○. When only the cold seal adhesive strength was obtained, the cold seal adhesive property was evaluated as x. Example 1 The evaluation results of the cold seal adhesive are shown in Table 1.

(Iii) Evaluation of blocking resistance The coated sheet of Example 1 was folded in two so that the adhesive layer was overlapped with the coated sheet, and a pressure of 7,840 N / m ² (a pressure applied in a normal state) ) And left at 20 ° C. for 24 hours. Thereafter, the superposed surface is peeled off by pulling the base sheet of the superposed surface by hand,
The peeled surface was visually observed. In the case where there was no resistance at the time of peeling and no damage was observed on the surface of the cold seal adhesive layer, it was evaluated as ○. The case where there was resistance during peeling and damage was observed on the surface of the cold seal adhesive layer was evaluated as x. Table 1 shows the evaluation results of Example 1.

(Iv) Evaluation of abrasion resistance The surface of the adhesive layer of the coated sheet of Example 1 was measured using a Gakushin-type dyed material friction fastness tester (manufactured by Daiei Kagaku Seiki Co., Ltd.).
After applying a force of 4.9 N and rubbing back and forth for 20 times, the state of the surface of the adhesive layer was visually observed. When there is no trace of the adhesive layer on the surface of the adhesive layer and no residue of the adhesive layer is observed, the case where the trace of the adhesive layer is observed or when the residue of the adhesive is observed is observed. X. Table 1 shows the evaluation results of Example 1.

(V) Evaluation of Removability and Material Destruction The coated sheet of Example 1 was folded in two so that the adhesive layers were overlapped, and a mail sealer for pressure bonding was used.
After applying a surface pressure of 10,000,000 N / m ² and applying pressure, the coated sheet was left for 30 minutes. afterwards,
Using a tensile tester (manufactured by Orientec Co., Ltd .: Tensilon), the coated sheet was subjected to a T-type peeling test at a pulling speed of 300 mm / min, and the crimped surface was peeled off. Then, the state of the peeled surface was visually observed to evaluate removability and material destruction. When the peeling occurs at the interface between the two adhesive layers at the bonded portion where the pressure is applied and the damage of the two adhesive layers after peeling cannot be visually observed, the peeling can be performed again. When the damage of the adhesive layer could be visually observed or the destruction of the base sheet could be observed, the material was destructed. Example 1 The evaluation results of the cold seal adhesive are shown in Table 1.

Example 2 The urethane resin of Example 1 was replaced with Luphe manufactured by BASF.
A cold seal adhesive of Example 2 was obtained by using the same method as that described in Example 1 except that nD259U (trade name) was changed to 100 parts by weight. Using the same method as described in Example 1, the cold seal adhesive of Example 2 was evaluated. The results are shown in Table 1.

Example 3 A method similar to that of Example 1 was used except that the urethane resin of Example 1 was changed to 100 parts by weight of Dispercoll U42 (trade name) manufactured by Sumitomo Bayern Urethane Co., Ltd. A cold seal adhesive of Example 3 was obtained. Using the same method as described in Example 1, the cold seal adhesive of Example 3 was evaluated. Table 1 shows the results
It was shown to.

Example 4 An SBR latex was prepared using a resin having an average particle size of 0.1 μm.
Styrene-acrylic resin having a Tg of 95 ° C. (GD-903 (trade name), manufactured by NSC Japan Ltd.) (however, the styrene-acrylic resin is in an emulsion form)
A cold seal adhesive was obtained using the same method as that described in Example 1 except that the adhesive was changed to. Using the same method as described in Example 1, the cold seal adhesive of Example 4 was evaluated. The results are shown in Table 1.

Example 5 In Example 5, a cold seal adhesive was obtained using the same method as that described in Example 1 except that the calcined kaolin in Example 1 was changed to potato starch. Using the same method as described in Example 1, the cold seal adhesive of Example 5 was evaluated. The results are shown in Table 1.

[0115]

[Table 1]

Examples 6 to 8 show examples of the cold seal adhesive in which the release of the adhesive at the bonded portion that has been crimped results in material destruction. Example 6 (1) Production of Cold Seal Adhesive of Example 6 As a urethane resin (A), Dispercoll U42 (trade name) manufactured by Sumitomo Bayern Urethane Co., Ltd .: 100
Parts by weight Resin (D) is a styrene-acrylic resin having a Tg of 85 ° C. and an average particle diameter of 0.1 μm (Flexbond 289, manufactured by Air Products).
(Trade name)) (however, this styrene-acrylic resin is in the form of an emulsion): 10 parts by weight and potato starch: 13 parts by weight were blended to obtain a cold seal adhesive of Example 6. Was.

(2) Evaluation of Cold Seal Adhesive of Example 6 (i) Preparation of Coated Sheet A high-quality paper having a basis weight of 90 g / m ² was used as a base sheet, and the dry weight was 8 g on one side of the high-quality paper. / M ² , the cold seal adhesive of Example 6 is applied and dried to form an adhesive layer, and a coated sheet (hereinafter referred to as “Example 6”).
Coated sheet).

(Ii) Evaluation of Cold Seal Adhesion, Removability and Material Destruction After the coated sheet of Example 6 was pressed, the force required for peeling was measured to determine the cold seal adhesion. Was evaluated, and the removability and material destruction were evaluated by visually observing the state of the peeled surface. The coated sheet of Example 6 was folded in two so that the layers of the adhesive were overlapped with each other, and a pressure of 4,700,000 N / m ² was applied using a flat press to press the coated sheet. It was left for 30 minutes. afterwards,
Cold seal adhesion was evaluated by performing a T-type peel test at a tensile speed of 300 mm / min using a tensile tester (manufactured by Orientec: Tensilon). When a cold seal adhesive force of 10 N / m or more can be obtained when peeling off the crimped surface, the cold seal adhesiveness is evaluated as ○. When a cold seal adhesive force of less than 10 N / m is obtained, cold seal adhesiveness is obtained. The property was evaluated as x. next,
The re-peelability and material destruction were evaluated by visually observing the surface obtained by peeling. The material was destructed when the surface obtained by peeling was visually observed for damage or when the substrate sheet was broken during peeling. When no damage could be visually observed on the peeled surface, it was determined that the film could be peeled again. Example 6 Table 2 shows the evaluation results of the cold seal adhesive.

(Iii) Evaluation of blocking resistance and abrasion resistance Evaluation of the blocking resistance and abrasion resistance was performed by using the coated sheet of Example 6 instead of the coated sheet of Example 1. Was performed in the same manner as in the evaluation of blocking resistance and abrasion resistance described in Example 1. The evaluation results of the cold seal adhesive of Example 6 are shown in Table 2.

Example 7 As a urethane resin (A), Dispercoll U42 (trade name) manufactured by Sumitomo Bayern Urethane Co., Ltd .: 100
The cold seal adhesive of Example 7 was obtained by blending so as to have a composition of parts by weight and potato starch: 13 parts by weight. Using the same method as described in Example 6, the cold seal adhesive of Example 7 was evaluated.
The results are shown in Table 2.

Example 8 As a urethane resin (A), Dispercoll U42 (trade name) manufactured by Sumitomo Bayern Urethane Co., Ltd .: 100
Parts by weight and the polyamide resin (C) are blended so as to have a composition of 8 parts by weight of polyamide (this polyamide is in the form of an emulsion), 12 parts by weight of tackifying resin, and 13 parts by weight of potato starch. Thus, a cold seal adhesive of Example 8 was obtained. Using the same method as described in Example 6, the cold seal adhesive of Example 8 was evaluated.
The results are shown in Table 2.

[0122]

[Table 2]

Since the present invention is configured as described above, the following effects can be obtained.

The cold seal adhesive of the present invention is a water-type cold seal adhesive containing a urethane resin (A), and at least 20% by weight of a urethane resin. Alleviates at least one of the problems associated with the conventional cold seal adhesives used, i.e., heat, light, oxygen, etc., can degrade adhesion, and can cause agglomerates during compounding or coating. In addition, blocking resistance, adhesiveness, and printability (related to offset printing, gravure printing, printing with a non-impact printer, and the like) can be improved.

The urethane resin (A) of the cold seal adhesive of the present invention was prepared by mixing the polyol and the polyisocyanate at a weight ratio of 1 / polyol / polyisocyanate.
The cold seal adhesiveness can be improved by polymerizing and producing the monomer mixture of 1 to 19/1. Furthermore,
By setting the Tg of the urethane resin (A) of the cold seal adhesive of the present invention to 50 ° C. or less, the cold seal adhesiveness can be improved.

Further, the cold seal adhesive of the present invention
By further including the polyolefin-based resin (B) and / or the polyamide-based resin (C), the wear resistance, the blocking resistance, and the removability can be improved. Furthermore, the cold seal adhesive of the present invention is a resin other than (A), (B), and (C), and has at least one kind of a resin (D) having a Tg of −30 ° C. or more. By containing, the blocking resistance, the adhesion to the base sheet, and the abrasion resistance can be improved. When the cold seal adhesive of the present invention contains, as the resin (D), at least one selected from a synthetic rubber-based resin and a vinyl-based resin, the blocking resistance, the adhesion to the base sheet, and the resistance to the base resin are improved. Abrasion can be improved.

[Brief description of the drawings]

FIG. 1 is an illustration of a bi-fold confidentiality postcard.

FIG. 2 is an explanatory diagram of an envelope.

FIG. 3 is an explanatory diagram of a half-fold business form.

FIG. 4 is an explanatory diagram of a two-sheet business form.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base sheet 2 Adhesion part 3 Bi-fold confidential postcard 4 Envelope 5 Bi-fold business form 6 Two-ply business form

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C09J 121/00 C09J 121/00 123/00 123/00 157/00 157/00 177/00 177/00 ( 72) Inventor Yoshio Yoshida 1-15-8-203 Tamako, Ibaraki-shi, Osaka (72) Inventor Denny's Perry United States 08807 New Jersey Bridgewater, Findern Avenue 10th F-term (reference) 2C005 WA03 4J040 BA012 CA032 CA072 CA082 DA002 DA022 DA102 DA182 DB022 DD022 DE022 DF012 DF022 DF082 DF092 EF051 EF281 EG002 EG022 JB09 LA02 MA09 MA10 MB03 MB09 NA10

Claims (15)

[Claims] 1. A water-based cold seal adhesive comprising a urethane resin (A), comprising at least 20% by weight.
Is a urethane resin. 2. The urethane resin (A) is produced by polymerizing a monomer mixture having a weight ratio of polyol to polyisocyanate (polyol / polyisocyanate) of 1/1 to 19/1. The cold seal adhesive according to claim 1, wherein 3. The cold seal adhesive according to claim 1, wherein the urethane resin (A) has a Tg of 50 ° C. or lower. 4. The cold seal adhesive according to claim 1, further comprising a polyolefin resin (B). 5. The cold seal adhesive according to claim 1, further comprising a polyamide resin (C). 6. A resin other than (A), (B) and (C), which further comprises at least one resin (D) having a Tg of -30 ° C. or higher. The cold seal adhesive according to any one of claims 1 to 5, wherein 7. The cold seal adhesive according to claim 6, wherein the resin (D) is at least one selected from a synthetic rubber resin and a vinyl resin. 8. An adhesive portion on which the cold seal adhesive according to claim 1 is applied to form an adhesive layer. 9. A cold seal adhesive is applied to the surface of the base sheet to be printed and dried to form an adhesive layer, and information is printed on the surface to be printed. 9. The bonding part according to claim 8, wherein a part and the other part are folded so as to be in contact with each other, and the two folded adhesive layers are overlapped so as to be in contact with each other, and the two are pressure-bonded together. 10. A cold seal adhesive is applied to the surface of the base sheet to be printed and dried to form an adhesive layer,
After printing the information on the surface to be printed, the printed surface is coated with a cold seal adhesive and dried to form an adhesive layer, and the adhesive layer on both surfaces. 9. The bonding portion according to claim 8, wherein the bonding portions are overlapped so as to be in contact with each other and are integrally pressed. 11. Applying a cold seal adhesive to a portion of the base sheet where no information is to be printed and which should be sealed so that the information can be concealed, followed by drying to form an adhesive layer 9. The method according to claim 8, wherein the coated part is folded so that a part of the coated part and the other part are in contact with each other, and the folded adhesive layers are overlapped so as to be in contact with each other, and the two parts are integrally pressed. Adhesion site. 12. After applying a cold seal adhesive to a portion of the base sheet where no information is to be printed and where the information is to be sealed so as to conceal the information, and drying it, an adhesive layer is formed. Apply the cold seal adhesive to the area to be sealed so that the information on the other surface can be concealed, and then dry and form an adhesive layer so that the applied area and the area where the adhesive layer is formed overlap each other. The bonding portion according to claim 8, wherein the two portions are integrally pressed. 13. A confidential postcard having the adhesion site according to claim 9 or 10. 14. An envelope having the bonding portion according to claim 11. 15. A business form having the adhesion site according to claim 11. Description: