JP2007002024A - Pressure-sensitive adhesive sheet for blood bag - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressure-sensitive adhesive sheet for blood bags excellent in adhesiveness to the blood bags made of a soft polyvinyl chloride resin, hardly causing reduction in strength and hardly generating floating or peeling after autoclave treatment and preservation at low temperatures and having processability required as the pressure-sensitive adhesive sheet. <P>SOLUTION: The pressure-sensitive adhesive sheet has an adhesive layer on one side of a base support material. The adhesive layer is formed by using an adhesive composition comprising a copolymer and a crosslinking agent. The copolymer is prepared by copolymerizing a monomer mixture comprising 60-96 mass% (a) n-butyl acrylate, 1.0-4.0 mass% (b) methyl methacrylate, 1.2-3.3 mass% (c) ethylenic unsaturated carboxylic acid, 0.2-0.8 mass% (d) OH-containing unsaturated monomer and 0-37.6 mass% (e) ethylenic unsaturated monomer except the above ingredients and has 600,000-1,000,000 weight average molecular weight. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is an adhesive sheet for blood bags, more specifically, it has excellent adhesion to a blood bag made of soft vinyl chloride resin, and is less susceptible to strength reduction, floating and peeling even after autoclaving or low-temperature storage. The present invention relates to a blood bag pressure-sensitive adhesive sheet having processability required as a sheet.

Conventionally, a soft vinyl chloride resin bag is often used as a blood bag for containing blood. The blood bag is used with a label on which information related to blood is attached.
When the attached label is subjected to steam sterilization such as autoclave treatment or steam sterilization treatment, the stickiness of the label decreases due to the plasticizer contained in the soft vinyl chloride resin, or due to heat shrinkage of the soft vinyl chloride resin, May be lifted or peeled off. If the label is peeled off from the blood bag, the blood information becomes unknown and becomes a serious problem. Even in that case, if the label is simply peeled off, the peeled blood bag can be disposed of, but if for some reason the labels are peeled off for some reason, they are replaced and reapplied. The wrong blood information blood bag will be used, which becomes a more fatal problem.
In addition, labels printed on the product name, volume, ingredient display, manufacturer, etc. are used as labels for blood bags, but in recent years, a management system using barcodes has been established, and these are displayed on blood back labels. There are not a few cases that use the. By printing the barcode on the label, not only the back information display, but also the information and history management (traceability) for each back (blood), and by utilizing it, prevention of medical accidents can be prevented. It becomes possible.
In addition, as a conventional blood bag label, a paper-based label has been often used. When such a label is applied to a blood bag, it can withstand centrifugal force due to insufficient strength of the label base material during processing in a centrifuge for separation into components such as normal blood cell components and plasma components. The printed information on the label surface becomes unclear due to friction with the wall surface, blood back surface, etc., or water vapor during autoclaving, and can be read with a barcode reader. Problems such as inability to occur. Therefore, there is a strong demand for a film base material that is superior in strength and scratch resistance as compared with a paper base material and also has high moisture resistance and printability. However, while the film substrate has the advantages described above, the strength of the film itself is strong, so that the adhesive and pressure-sensitive adhesive are subject to stress applied during autoclave treatment, steam sterilization treatment, centrifugation treatment, thermal shrinkage of the back, etc. There is a problem that it is difficult to withstand the generated distortion, and it tends to float and peel off.
To solve these problems, blood back labels using film base materials often use heat sealants with excellent adhesive strength (heat-sensitive adhesives), and for blood bags that do not easily float or peel off. Heat seal agents (heat-sensitive adhesives) and the like have been proposed (see, for example, Patent Document 1).
An adhesive (pressure-sensitive adhesive) can also be used for the adhesive layer, but it is inferior in adhesive strength to blood bags, cohesive strength, and plasticizer resistance compared to heat sealants, so it is autoclaved or centrifuged. None of the materials sufficiently satisfied the required performance, such as floating or peeling after the separation process, or sticking out of the label end face. In particular, when steam sterilization (autoclave treatment) is performed, the plasticizer contained in the blood bag bleeds into the interface between the blood bag and the pressure-sensitive adhesive layer, or into the components of the pressure-sensitive adhesive layer. There was a problem that the label was liable to lift and peel off due to a decrease in force.
Advantages of using an adhesive include that no special equipment is required for application (no initial investment is required), that it is available at a relatively low cost, and that anyone can easily apply. The amount is also large. In recent years, the demand for pressure-sensitive adhesive labels using a film base material has further increased due to consideration for traceability and good appearance.
In such a background, in order to suppress the floating of the label, for example, a method of increasing the amount of (meth) acrylic acid to improve the adhesiveness or using a monomer that lowers the glass transition temperature of the pressure-sensitive adhesive, Attempts have been made to soften the agent. However, the former raises the glass transition temperature and causes low temperature adhesion. Further, the latter has a problem in the processing process such that the adhesive is likely to adhere to the blade during cutting at room temperature.
JP 2004-231915 A

  Under such circumstances, the present invention has excellent adhesiveness to a blood bag made of a soft vinyl chloride resin, and is less susceptible to strength reduction, floating and peeling even after autoclaving or low-temperature storage. The object of the present invention is to provide a blood bag pressure-sensitive adhesive sheet having the necessary processability as a sheet.

As a result of intensive studies to develop a blood bag pressure-sensitive adhesive sheet having the above-mentioned preferable properties, the present inventors have a specific composition and molecular weight for forming a pressure-sensitive adhesive layer provided on one side of a support substrate. By using a pressure-sensitive adhesive composition containing a copolymer and a crosslinking agent, it was found that the object can be achieved, and the present invention has been completed based on this finding.
That is, the present invention
(1) A pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer on one side of a supporting substrate, which is attached to a soft vinyl chloride resin blood bag, wherein the pressure-sensitive adhesive layer is
(A) n-butyl acrylate 60-96 mass%,
(B) 1.0 to 4.0% by mass of methyl methacrylate,
(C) 1.2 to 3.3% by mass of an ethylenically unsaturated carboxylic acid,
(D) 0.2 to 0.8% by mass of a hydroxyl group-containing unsaturated monomer, and (e) 0 to 37.6% by mass of an ethylenically unsaturated monomer other than the above,
A blood bag adhesive, characterized in that it is formed using a copolymer having a weight average molecular weight of 600,000 to 1,000,000 obtained by copolymerizing a monomer mixture containing Sheet,
(2) (A) A holding force of 40 ° C. and a 9.8 N load in a holding power test described in JIS Z 0237 is 40,000 seconds or more, and (B) a sticking when a soft vinyl chloride resin sheet is used as an adherend. After 24 hours, the adhesive strength at 23 ° C. (180 ° peeling method, pulling speed 300 mm / min) is 1.8 to 20 N / 25 mm, and (C) is attached to a soft vinyl chloride resin sheet, and autoclaved (121 ° C., The blood bag according to (1) above, wherein the adhesive strength at 23 ° C. after the high-pressure steam sterilization treatment (for 30 minutes) (180 ° peeling method, pulling speed 300 mm / min) is 15.0 to 40 N / 25 mm. Adhesive sheet,
(3) In the monomer mixture, the total content of (c) the ethylenically unsaturated carboxylic acid and (d) the hydroxyl group-containing unsaturated monomer is 2.0 to 3.5% by mass (1) ) Or (2) blood bag pressure-sensitive adhesive sheet,
(4) The adhesive sheet for blood bag according to any one of (1) to (3) above, wherein the adhesive composition contains 0.1 to 55 parts by mass of a tackifier per 100 parts by mass of the copolymer; And (5) the adhesive sheet for blood bag according to any one of the above (1) to (4), wherein the crosslinking agent comprises a polyisocyanate compound,
Is to provide.

  According to the present invention, it has excellent adhesiveness to a blood bag made of a soft vinyl chloride resin, and is less susceptible to strength reduction, floating and peeling even after autoclaving or low-temperature storage, and has the necessary workability as an adhesive sheet. The adhesive sheet for blood bags which has can be provided.

The blood bag pressure-sensitive adhesive sheet of the present invention (hereinafter sometimes referred to simply as a pressure-sensitive adhesive sheet) is a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer on one side of a support substrate, which is attached to a blood bag made of a soft vinyl chloride resin. .
There is no particular limitation on the support substrate used for this adhesive sheet, and a known plastic film or sheet, paper, or synthetic paper having a cavity inside can be used. However, mechanical strength, printability, and barcode readability can be used. It is preferable to use a plastic substrate that is excellent in the above and has high adaptability to traceability.
There are no particular restrictions on this plastic substrate, for example, polyolefin resins such as polyethylene resins and polypropylene resins, polyester resins such as polybutylene terephthalate resins and polyethylene terephthalate resins, acetate resins, ABS resins, polystyrene resins, vinyl chloride resins, etc. Plastic film and sheet. These films and sheets may be unstretched, or may be stretched in a uniaxial direction such as longitudinal or lateral, or in a biaxial direction.
Although there is no restriction | limiting in particular in the thickness of such a plastic substrate, Usually, about 10-250 micrometers, Preferably it is 25-200 micrometers.

The plastic substrate may be colored or colorless and transparent. Moreover, printing, printing, etc. may be given to the surface or back surface of the base material. In order to effectively perform printing or printing, the plastic substrate may be provided with a heat-sensitive recording layer, or a print image-receiving layer capable of performing thermal transfer, inkjet recording, laser printing, a printability improving layer, or the like. Good.
Moreover, in order to improve the adhesiveness with the layer provided on the said plastic base material, surface treatments, such as an oxidation method and an uneven | corrugated method, can be given if desired. Examples of the oxidation method include corona discharge treatment, plasma treatment, chromic acid treatment (wet), flame treatment, hot air treatment, ozone / ultraviolet irradiation treatment, and examples of the unevenness method include a sand blast method, a solvent, and the like. Treatment methods and the like. These surface treatment methods are appropriately selected depending on the type of the substrate, but in general, the corona discharge treatment method is preferably used from the viewpoints of effects and operability. Moreover, primer treatment can also be performed.

In the pressure-sensitive adhesive sheet of the present invention, for the formation of the pressure-sensitive adhesive layer on one side of the support substrate, (a) n-butyl acrylate, (b) methyl methacrylate, (c) an ethylenically unsaturated carboxylic acid, ( d) A pressure-sensitive adhesive composition containing an acrylic copolymer obtained by copolymerizing a monomer mixture containing a hydroxyl group-containing unsaturated monomer and optionally (e) an ethylenically unsaturated monomer other than those described above. Things are used.
Examples of the ethylenically unsaturated carboxylic acid of component (c) include acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, citraconic acid, etc., and these may be used alone. You may use combining more than a seed.
Further, as the hydroxyl group-containing unsaturated monomer of component (d), 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, (meth) Examples include 2-hydroxybutyl acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, etc., and these may be used alone or in combination of two or more. May be.

  Furthermore, as the (e) component ethylenically unsaturated monomer used in some cases, for example, (meth) acrylic acid alkyl esters other than the above (a) and (b) components; acetoacetoxymethyl (meth) acrylate, etc. (Meth) acrylic acid functional group-substituted alkyl ester: acrylamide, methacrylamide, N-methylacrylamide, N-methylmethacrylamide, N-methylolacrylamide, N-methylolmethacrylamide, N, N-dimethylacrylamide, N, N- Acrylamides such as dimethylmethacrylamide; (meth) acrylates such as monomethylaminoethyl (meth) acrylate, monoethylaminoethyl (meth) acrylate, monomethylaminopropyl (meth) acrylate, monoethylaminopropyl (meth) acrylate Monoalkylamino acrylate Vinyl esters such as vinyl acetate and vinyl propionate; olefins such as ethylene, propylene and isobutylene; halogenated olefins such as vinyl chloride and vinylidene chloride; styrene monomers such as styrene and α-methylstyrene; Diene monomers such as butadiene, isoprene, and chloroprene; nitrile monomers such as acrylonitrile and methacrylonitrile, and the like may be used. These may be used alone or in combination of two or more. Also good.

The monomer mixture used as a raw material for the acrylic copolymer contained in the pressure-sensitive adhesive composition is (a) 60-96% by mass, preferably 63-96% by mass, and (b) n-butyl acrylate. Methyl methacrylate is 1.0 to 4.0% by mass, preferably 1.5 to 3.5% by mass, and (c) ethylenically unsaturated carboxylic acid is 1.2 to 3.3% by mass, preferably 1. 4 to 3.0% by mass, (d) 0.2 to 0.8% by mass of hydroxyl group-containing unsaturated monomer, preferably 0.3 to 0.7% by mass, and (e) ethylene-based other than the above The unsaturated monomer is contained in an amount of 0 to 37.6% by mass, preferably 0 to 33.8% by mass.
When the content of n-butyl acrylate in the monomer mixture is 60% by mass or more and the content of methyl methacrylate is 1.0% by mass or more, the plasticizer resistance is increased and sterilization is performed. The subsequent lifting of the pressure-sensitive adhesive sheet can be suppressed.
Further, by adjusting the content of methyl methacrylate to 4.0% by mass or less, the adhesive strength at room temperature is improved, and by setting the content of ethylenically unsaturated carboxylic acid to 1.2% by mass or more. Adhesive strength and cohesive strength are improved, and by adjusting it to 3.3% by mass or less, adhesive strength at room temperature is improved.
Furthermore, by setting the content of the hydroxyl group-containing unsaturated monomer to 0.2% by mass or more, the adhesion to the plastic substrate and the cohesive force of the adhesive are effectively improved, and 0.8% by mass. By making it below, it is possible to suppress a decrease in adhesive strength.
In the present invention, the total content of the ethylenically unsaturated carboxylic acid and the hydroxyl group-containing unsaturated monomer in the monomer mixture is preferably 2.0 to 3.5% by mass. By setting the total content to 2.0% by mass or more, adhesive force and cohesive force necessary for holding the pressure-sensitive adhesive sheet can be obtained. By setting the total content to 3.5% by mass or less, good initial adhesiveness can be obtained. Is maintained.

By copolymerizing the monomer mixture according to a conventional method, an acrylic copolymer which is an adhesive component in the adhesive composition is obtained.
This acrylic copolymer requires a weight average molecular weight of 600,000 to 1,000,000 in order to improve the cohesive strength of the pressure-sensitive adhesive. If the weight average molecular weight is less than 600,000, the problem of floating / peeling or ouse (adhesive sticking out) due to migration of the plasticizer tends to occur, and if it exceeds 1,000,000, the viscosity increases and solution polymerization becomes difficult. Inconvenience occurs in manufacturing. In addition, the said weight average molecular weight is the value of polystyrene conversion measured by the gel permeation chromatography (GPC) method.
The acrylic copolymer is not particularly limited as to its copolymerization form, and may be any of random, block, and graft copolymers. The glass transition temperature is preferably −60 to −40 ° C., more preferably −56 to −45 ° C. If this glass transition temperature is −60 ° C. or higher, the problem of floating / peeling and ouse due to the migration of the plasticizer is unlikely to occur, and if it is −40 ° C. or lower, good initial adhesive strength is easily obtained.

In the said adhesive composition, it is necessary to contain a crosslinking agent with the said acrylic type copolymer. There is no restriction | limiting in particular as this crosslinking agent, For example, a conventionally well-known crosslinking agent, for example, a polyisocyanate compound, an epoxy compound, an aluminum chelate compound, an ethyleneimine compound etc. are mentioned. Although these crosslinking agents may be used individually by 1 type and may be used in combination of 2 or more type, the crosslinking agent containing a polyisocyanate compound is suitable.
Examples of the polyisocyanate compound include aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, and xylylene diisocyanate, aliphatic polyisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, and hydrogenated diphenylmethane diisocyanate. Polyisocyanates and the like, and biurets, isocyanurates, and adducts that are a reaction product with a low molecular active hydrogen-containing compound such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, castor oil, etc. Derivatives can be mentioned.
The amount of the crosslinking agent used is appropriately selected according to the type of the crosslinking agent so as to obtain good adhesion to the support substrate, plasticizer resistance, adhesive strength (initial adhesiveness), holding power, and the like. The amount is usually selected in the range of 0.001 to 30 parts by mass, preferably 0.01 to 15 parts by mass with respect to 100 parts by mass of the acrylic copolymer.

The pressure-sensitive adhesive composition preferably contains a tackifier. There is no particular limitation on the tackifier, for example, polymerized rosin, polymerized rosin ester, rosin derivatives such as rosin derivatives and hydrides thereof, polyterpene resins, aromatic modified terpene resins and hydrides thereof, terpene phenol resins, coumarone Indene resins, aliphatic petroleum resins, aromatic petroleum resins and their hydrides, aliphatic / aromatic copolymer petroleum resins, styrenic low molecular weight polymers, and the like can be used. These may be used individually by 1 type and may be used in combination of 2 or more type.
The usage-amount of this tackifier is 0.1-55 mass parts normally with respect to 100 mass parts of said acrylic copolymers. If the amount of the tackifier used is within the above range, the adhesion to the blood bag is effectively improved and the cohesive force necessary for processing the pressure-sensitive adhesive sheet is maintained by keeping the amount added within a certain range. And the occurrence of ouse can be suppressed. The preferable usage-amount of this tackifier is 11-44 mass parts.
In the pressure-sensitive adhesive composition, various additives can be appropriately contained as necessary within the range where the effects of the present invention are not impaired. Examples of the additive include a filler, a colorant, an antioxidant, and an ultraviolet absorber.
Here, examples of the filler include inorganic fillers such as titanium oxide, silica, calcium carbonate, barium sulfate, and talc, and organic fillers such as starch. Examples of the antioxidant include anilide, phenol, phosphite, and thioester, and examples of the ultraviolet absorber include benzophenone and benzotriazole.

The adhesive composition can contain a diluent as necessary. Examples of the diluent include aromatic hydrocarbon compounds such as benzene, toluene and xylene, aliphatic hydrocarbon compounds such as hexane, heptane, octane, nonane and decane, and ketones such as methyl ethyl ketone, diethyl ketone and diisopropyl ketone. Can be mentioned. These diluents may be used individually by 1 type, and may mix and use 2 or more types.
There is no restriction | limiting in particular about the solid content density | concentration in the said adhesive composition, It is good to adjust with the said diluent so that it may become the viscosity which can apply | coat the said composition.
There is no restriction | limiting in particular about the manufacturing method of the adhesive sheet of this invention, The said adhesive composition may be directly apply | coated and dried to a support base material, and an adhesive layer may be formed, or an adhesive composition is provided on a peeling sheet. May be applied and dried to provide a pressure-sensitive adhesive layer, which is then adhered to a supporting substrate, and the pressure-sensitive adhesive layer may be transferred. In this case, the release sheet may be adhered as it is without being peeled off if desired, and may be peeled off when the pressure-sensitive adhesive sheet is used.
The coating method of the pressure-sensitive adhesive composition is not particularly limited, and conventionally known coating methods can be used. For example, knife coater, roll coater, roll knife coater, gravure coater, air knife coater, bar coater And a method using a coating apparatus such as a die coater or a curtain coater.
The thickness of the pressure-sensitive adhesive layer provided on the support substrate is usually about 10 to 50 μm, preferably about 15 to 35 μm.

In the pressure-sensitive adhesive layer thus formed, the acrylic copolymer in the pressure-sensitive adhesive layer is cross-linked by a cross-linking agent, and thus the pressure-sensitive adhesive sheet obtained can have the properties described later.
Examples of the release sheet include paper substrates such as glassine paper, coated paper, cast coated paper, laminated paper obtained by laminating a thermoplastic resin such as polyethylene on these paper substrates, or polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate. Examples include those obtained by applying a release agent such as a silicone resin, an alkyd resin, a fluororesin, or a long-chain alkyl-containing resin to a plastic film such as a polyester film such as phthalate or a polyolefin film such as polypropylene or polyethylene. Although there is no restriction | limiting in particular about the thickness of this peeling sheet, Usually, it is about 30-200 micrometers.
The thickness of the pressure-sensitive adhesive sheet (with a release sheet) of the present invention thus obtained is preferably a thickness that can be introduced into a printer or the like, and is usually about 50 to 300 μm.

Next, the blood bag pressure-sensitive adhesive sheet of the present invention preferably satisfies all the following properties (A) to (C).
First, as a property of (A), it is preferable that the holding power of 40 degreeC and a 9.8N load in the holding power test as described in JISZ0237 is 40,000 second or more. If this holding force is 40,000 seconds or more, the adhesive can be prevented from adhering to the blade during cutting at room temperature, the workability is good, and from the end face of the adhesive sheet after autoclaving treatment It is possible to suppress the sticking out of the pressure-sensitive adhesive.
Next, as a property of (B), an adhesive sheet is attached to a soft vinyl chloride resin sheet, and the strength (adhesiveness) at 23 ° C. when peeled at a pulling speed of 300 mm / min by a 180 ° peeling method after 24 hours of sticking. Force) is preferably 1.8 to 20 N / 25 mm, and more preferably 2.1 to 15 N / 25 mm. If the peel strength (adhesive strength) is in the range of 1.8 to 20 N / 25 mm, the adhesive sheet is less likely to float or peel off after application, and the adhesive sheet may be displaced or fall off before post-processing or autoclaving. In addition, when the adhesive sheet is pasted and shifted from a predetermined position, it can be pasted again.

Furthermore, as a property of (C), after being attached to a soft vinyl chloride resin sheet, and then autoclaved (121 ° C., high pressure steam sterilization) for 30 minutes, it is peeled off at a pulling speed of 300 mm / min by a 180 ° peeling method. The strength at 23 ° C. (adhesive strength) is preferably 15.0 to 40 N / 25 mm, and more preferably 17 to 29 N / 25 mm. If this peel strength (adhesive strength) is in the range of 15.0 to 40 N / 25 mm, it is possible to suppress floating / peeling under most conditions of use, as well as autoclave treatment, steam sterilization treatment, and centrifugation treatment. The pressure-sensitive adhesive sheet can sufficiently withstand stress applied at times and distortion due to thermal shrinkage of the back.
The pressure-sensitive adhesive sheet of the present invention may be a flat sheet or may be rolled up. Moreover, although it uses for a display label, a management label, etc. as an object for blood bags made from a soft vinyl chloride resin, it can also be used for the other various uses which stick an adhesive layer.
The blood bag pressure-sensitive adhesive sheet of the present invention usually has blood information such as blood type and blood collection date / time printed on the surface of the supporting substrate. As the printing / printing method, (1) thermal transfer thermal method, (2) direct thermal method, (3) laser method, (4) other methods (dot matrix method, ink jet method, etc.) can be adopted. The pressure-sensitive adhesive sheet is usually attached to the blood bag before the blood is filled into the blood bag.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
In addition, the performance of the adhesive sheet obtained in each example was evaluated according to the method shown below.
(1) Adhesive strength Adhesive sheets are attached to the surface of a blood bag made of a soft vinyl chloride resin according to JIS Z 0237, and after 24 hours and after autoclaving (121 ° C., 30 minutes), each is peeled 180 °. Thus, the strength when peeled at a pulling speed of 300 mm / min was measured.
(2) Holding force A pressure-sensitive adhesive sheet is attached to a stainless steel plate having a thickness of 2 mm, and a weight of 1 kg under conditions of a temperature of 40 ° C., a load of 9.8 N, and a bonding area of 25 mm × 25 mm (measurement method based on JIS Z 0237). The time until it fell was measured.
(3) Initial sticking property Assuming that the adhesive sheet is re-applied, immediately after the adhesive sheet is applied to the surface of the blood bag made of soft vinyl chloride resin, the adhesive sheet is peeled off and the wrinkles and base material are stretched on the adhesive sheet. Then, it was confirmed whether a large curl was generated and the strength at the time of peeling had a strength necessary for holding the pressure-sensitive adhesive sheet, and evaluated according to the following criteria.
◎ Adhesive sheet has appropriate adhesive strength and can be re-applied ○ Initial adhesive strength or re-attachability is slightly inferior, but has no practical problem △ Initial strength of adhesive sheet or re-applicability Inferior to the above, there is a problem in practical use x The initial strength of the adhesive sheet is considerably inferior, or it is difficult to hold the label due to lack of reattachability (4) Autoclave suitability The adhesive sheet is made of a soft polyvinyl chloride resin blood bag The sample was affixed to the surface and allowed to stand for 30 minutes or longer, and after floating and peeling after autoclaving (121 ° C., 30 minutes), it was visually observed and evaluated according to the following criteria.
◎ Adhesive sheet does not float / peel off ○ Adhesive sheet floats / peel off slightly, but there are no practical problems △ Adhesive sheet floats / peeles off, has practical problems × Adhesive sheet completely lifted・ Things to be peeled off (5) Centrifugation test Adhesive sheet is affixed to a blood bag made of soft vinyl chloride resin, autoclaved (121 ° C, 30 minutes), then centrifuged (3000 G, 20 minutes), and the adhesive sheet is lifted or peeled off Were visually observed and evaluated according to the following criteria.
◎ Adhesive sheet does not float / peel off ○ Adhesive sheet floats / peel off slightly, but there are no practical problems △ Adhesive sheet floats / peeles off, has practical problems × Adhesive sheet completely lifted・ Things to be peeled off (6) Ouse (adhesiveness of adhesive)
The pressure-sensitive adhesive sheet was affixed to a blood bag made of soft vinyl chloride resin, the appearance after autoclaving (121 ° C., 30 minutes) was visually confirmed, and evaluated according to the following criteria.
◎ No wrinkle is confirmed on the end face of the adhesive sheet. ○ There is a slight ouse on the end face of the adhesive sheet, but there is no practical problem. △ There is a problem on the end face of the adhesive sheet. Items to be confirmed (7) Comprehensive evaluation Initial adhesiveness when the adhesive sheet is attached to a blood bag made of soft vinyl chloride resin, appearance after autoclaving or centrifugation, adhesive strength to blood bag, and ouse Whether or not it can be used as an adhesive sheet for blood bags is comprehensively determined from the presence or absence, and evaluated according to the following criteria.
◎ Optimal as an adhesive sheet for blood bags. ○ Excellent performance as an adhesive sheet for blood bags and judged to be usable. △ What may cause practical problems as an adhesive sheet for blood bags. It is judged that it is difficult to use as an adhesive sheet for blood bags. As a blood bag made of a soft vinyl chloride resin used in the above test, a plasticized polychlorinated resin having an arithmetic average surface roughness Ra = 6.3 μm. A vinyl film was used.

Example 1
A single amount consisting of 94.5% by mass of n-butyl acrylate, 2.5% by mass of methyl methacrylate, 2.5% by mass of acrylic acid and 0.5% by mass of 2-hydroxyethyl methacrylate using ethyl acetate as a solvent. The copolymer mixture was copolymerized to prepare a copolymer solution containing an acrylic copolymer having a weight average molecular weight of 800,000 at a concentration of 40.0% by mass.
Next, in this copolymer solution, a rosin resin [made by Arakawa Chemical Industries, trade name “KE359”, ultra-light rosin ester resin, softening point 100 as a tackifier with respect to 100 parts by mass of the acrylic copolymer. 20 parts by mass and petroleum resin [trade name “FTR-6100” manufactured by Mitsui Chemicals, aliphatic / aromatic copolymer petroleum resin, softening point 95 ° C.] 20 parts by mass, and then as a crosslinking agent 1.0 mass part of polyisocyanate [Toyo Ink Manufacturing Co., Ltd. make, brand name "BHS-8515"] was added, and the adhesive composition was prepared.
Next, the pressure-sensitive adhesive composition was dried by a roll knife coater on the release-treated surface of a release sheet [trade name “SP-8K Ao”, manufactured by Lintec Corporation, silicone resin release agent / glassine paper] having a thickness of 70 μm. The coated film was applied to a thickness of 30 μm and dried at 90 ° C. for 2 minutes to form an adhesive layer. Subsequently, it was bonded to a polypropylene synthetic paper film [manufactured by YUPO Corporation, trade name “YUPO SGP80”, thickness 80 μm] provided with a print receiving layer, to produce an adhesive sheet.
After blood information was printed on the substrate surface of this pressure-sensitive adhesive sheet, it was cut into a label size (10 cm × 10 cm), the release sheet was peeled off, and the pressure-sensitive adhesive sheet was attached to the surface of the blood bag made of soft vinyl chloride resin. At the time of sticking the adhesive sheet, the ease of peeling of the adhesive sheet was not recognized. After leaving in this state for one month, the adhesive state of the pressure-sensitive adhesive sheet was visually observed, but there was no lifting or peeling. The adhesive strength, holding strength measurement test, autoclave suitability, and centrifugation test were evaluated.
The results are shown in Table 1 together with the properties of the pressure-sensitive adhesive composition.

Example 2
In Example 1, except that no tackifier was added, a pressure-sensitive adhesive composition was prepared in the same manner as in Example 1, and a pressure-sensitive adhesive sheet was further produced. The results are shown in Table 1.
Example 3
A pressure-sensitive adhesive composition was prepared in the same manner as in Example 1 except that the weight average molecular weight of the acrylic copolymer was changed to 600,000 in Example 1, and a pressure-sensitive adhesive sheet was further produced. The results are shown in Table 1.
Example 4
In Example 1, the monomer composition was 64.5% by mass of n-butyl acrylate, 30.0% by mass of 2-ethylhexyl acrylate, 2.5% by mass of methyl methacrylate, 2.5% by mass of acrylic acid, and A pressure-sensitive adhesive composition was prepared in the same manner as in Example 1 except that 2-hydroxyethyl methacrylate was 0.5% by mass, and a pressure-sensitive adhesive sheet was prepared. The results are shown in Table 1.
Example 5
In Example 1, the monomer composition was 95.0% by mass of n-butyl acrylate, 2.5% by mass of methyl methacrylate, 2.0% by mass of methacrylic acid, and 0.5% by mass of 2-hydroxyethyl methacrylate. A pressure-sensitive adhesive composition was prepared in the same manner as in Example 1 except that the pressure-sensitive adhesive sheet was prepared. The results are shown in Table 1.

[note]
1) BA: n-butyl acrylate 2) 2EHA: 2-ethylhexyl acrylate 3) MMA: methyl methacrylate 4) AAc: acrylic acid 5) MAAc: methacrylic acid 6) HEMA: 2-hydroxyethyl methacrylate 7) Mw : Weight average molecular weight 8) Tg: Glass transition temperature 9) KE359: Rosin ester resin 10) FTR-6100: Petroleum resin 11) Mass parts of tackifier and crosslinking agent: Value relative to 100 parts by mass of copolymer

Comparative Example 1
In Example 1, the monomer composition was 50.0% by mass of n-butyl acrylate, 44.5% by mass of 2-ethylhexyl acrylate, 2.5% by mass of methyl methacrylate, 2.5% by mass of acrylic acid, and A pressure-sensitive adhesive composition was prepared in the same manner as in Example 1 except that 2-hydroxyethyl methacrylate was 0.5% by mass, and a pressure-sensitive adhesive sheet was prepared. The results are shown in Table 2.
Comparative Example 2
In Example 1, the monomer composition was 92.0% by mass of n-butyl acrylate, 5.0% by mass of methyl methacrylate, 2.5% by mass of acrylic acid, and 0.5% by mass of 2-hydroxyethyl methacrylate. A pressure-sensitive adhesive composition was prepared in the same manner as in Example 1 except that the pressure-sensitive adhesive sheet was prepared. The results are shown in Table 2.
Comparative Example 3
Example 2 is the same as Example 2 except that the monomer composition is 96.5% by mass of n-butyl acrylate, 3.0% by mass of acrylic acid, and 0.5% by mass of 2-hydroxyethyl methacrylate. Similarly, a pressure-sensitive adhesive composition was prepared, and a pressure-sensitive adhesive sheet was further produced. The results are shown in Table 2.
Comparative Example 4
In Example 1, the monomer composition was 95.0% by mass of n-butyl acrylate, 3.2% by mass of methyl methacrylate, 1.0% by mass of acrylic acid, and 0.8% by mass of 2-hydroxyethyl methacrylate. A pressure-sensitive adhesive composition was prepared in the same manner as in Example 1 except that the pressure-sensitive adhesive sheet was prepared. The results are shown in Table 2.

Comparative Example 5
In Example 1, the monomer composition was 93.0% by mass of n-butyl acrylate, 2.5% by mass of methyl methacrylate, 3.5% by mass of acrylic acid, and 1.0% by mass of 2-hydroxyethyl methacrylate. A pressure-sensitive adhesive composition was prepared in the same manner as in Example 1 except that the pressure-sensitive adhesive sheet was prepared. The results are shown in Table 2.
Comparative Example 6
In Example 2, the same composition as in Example 2 except that the monomer composition was 95.0% by mass of n-butyl acrylate, 2.5% by mass of methyl methacrylate, and 2.5% by mass of acrylic acid. A pressure-sensitive adhesive composition was prepared, and a pressure-sensitive adhesive sheet was further produced. The results are shown in Table 2.
Comparative Example 7
In Example 1, the monomer composition was 93.5% by mass of n-butyl acrylate, 2.5% by mass of methyl methacrylate, 2.0% by mass of acrylic acid, and 2.0% by mass of 2-hydroxyethyl methacrylate. A pressure-sensitive adhesive composition was prepared in the same manner as in Example 1 except that the pressure-sensitive adhesive sheet was prepared. The results are shown in Table 2.
Comparative Example 8
In Example 1, except that the weight average molecular weight of the acrylic copolymer was changed to 450,000, a pressure-sensitive adhesive composition was prepared in the same manner as in Example 1, and a pressure-sensitive adhesive sheet was further produced. The results are shown in Table 2.

[note]
1) BA, 2EHA, MMA, AAc, MAAc, HEMA, Mw, Tg, KE359, FTR-6100, the mass part of the tackifier and the mass part of the crosslinking agent are the same as the footnotes in Table 1.

As can be seen from Table 1, each of the pressure-sensitive adhesive sheets obtained in each Example has excellent properties as a pressure-sensitive adhesive sheet for blood bag application made of a soft vinyl chloride resin.
On the other hand, in Comparative Example 1, since it contains a large amount of 2-ethylhexyl acrylate and does not contain the necessary amount of n-butyl acrylate, the plasticizer resistance is reduced, and the adhesive strength after autoclaving is insufficient. Label floating occurred. In Comparative Example 2, the initial adhesive strength with increasing Tg was reduced due to the large amount of methyl methacrylate. Moreover, the adhesive strength of the autoclave was insufficient. Further, in Comparative Example 3, since methyl methacrylate was not contained at all, the plasticizer resistance and the cohesive force of the pressure-sensitive adhesive were insufficient, and the label was lifted or peeled off. In Comparative Example 4, the amount of the ethylenically unsaturated carboxylic acid and the hydroxyl group-containing unsaturated monomer serving as a crosslinking base point was small, and sufficient cohesive force was not obtained. For this reason, the initial adhesive strength was too high, and it was difficult to reattach. Ouse was also confirmed.
In Comparative Example 5, since the total amount of the ethylenically unsaturated carboxylic acid and the hydroxyl group-containing unsaturated monomer is too large, the cross-linking density of the pressure-sensitive adhesive is increased, the initial sticking property is inferior, and the label floats during autoclave and centrifugation. Occurred. Moreover, in Comparative Example 6, since the hydroxyl group-containing unsaturated monomer was not used, the cohesive force of the adhesive was insufficient. For this reason, ouse was generated. In Comparative Example 7, since a large amount of the hydroxyl group-containing unsaturated monomer was used, the degree of crosslinking increased, and as a result, a large label float occurred during autoclave or centrifugation. For this reason, it was difficult to use. In Comparative Example 8, since the molecular weight of the pressure-sensitive adhesive was set low, the cohesive force of the pressure-sensitive adhesive was insufficient, and the label was lifted off.

  The adhesive sheet for blood bag according to the present invention is excellent in sticking property to a blood bag made of soft vinyl chloride resin, and it is difficult to decrease in strength, float and peel even after autoclaving or low-temperature storage, and is necessary as an adhesive sheet It has excellent processability and is used for display labels and management labels for blood bags.

Claims (5)

A pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer on one side of a support substrate, which is attached to a soft vinyl chloride resin blood bag, wherein the pressure-sensitive adhesive layer is
(A) n-butyl acrylate 60-96 mass%,
(B) 1.0 to 4.0% by mass of methyl methacrylate,
(C) 1.2 to 3.3% by mass of an ethylenically unsaturated carboxylic acid,
(D) 0.2 to 0.8% by mass of a hydroxyl group-containing unsaturated monomer, and (e) 0 to 37.6% by mass of an ethylenically unsaturated monomer other than the above,
A blood bag adhesive, characterized in that it is formed using a copolymer having a weight average molecular weight of 600,000 to 1,000,000 obtained by copolymerizing a monomer mixture containing Sheet.   (A) Holding power of 40 ° C. and 9.8 N load in the holding power test described in JIS Z 0237 is 40,000 seconds or more, (B) 24 hours after application when a soft vinyl chloride resin sheet is used as an adherend The adhesive strength at 23 ° C. (180 ° peeling method, pulling speed 300 mm / min) is 1.8 to 20 N / 25 mm, and (C) is attached to a soft vinyl chloride resin sheet and autoclaved (121 ° C., high pressure for 30 minutes) The pressure-sensitive adhesive sheet for blood bag according to claim 1, wherein the adhesive strength at 23 ° C. after steam sterilization (180 ° peeling method, pulling speed 300 mm / min) is 15.0 to 40 N / 25 mm.   The total content of (c) an ethylenically unsaturated carboxylic acid and (d) a hydroxyl group-containing unsaturated monomer in the monomer mixture is 2.0 to 3.5% by mass. The adhesive sheet for blood bags as described.   The adhesive sheet for blood bags according to any one of claims 1 to 3, wherein the adhesive composition contains 0.1 to 55 parts by mass of a tackifier per 100 parts by mass of the copolymer. The pressure-sensitive adhesive sheet for blood bag according to any one of claims 1 to 4, wherein the crosslinking agent contains a polyisocyanate compound.