JP2019052213A - Ultraviolet-curable adhesive composition - Google Patents

Abstract

To provide an ultraviolet-curable adhesive composition which is low in VOC and can achieve good screen printability and good adhesiveness in a well-balanced manner.SOLUTION: The ultraviolet-curable adhesive composition of the present invention contains (A) a reactive polymer, (B) a polymerization initiator, (C) a monomer having a polymerizable double bond, and (D) a silicone-based compound. The component (A) contains a repeating unit derived from a (meth)acrylic monomer, contains 0.3 mmol/100 g or more and 40 mmol/100 g or less of functional groups containing a (meth)acryloyl skeleton, has a weight average molecular weight of 100,000 or more and 500,000 or less, and has a glass transition temperature of -55°C or higher and 0°C or lower. As the component (B), 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]-phenyl}-2-methyl-propan-1-one is contained.SELECTED DRAWING: None

Description

  The present invention relates to an ultraviolet curable pressure-sensitive adhesive composition.

  The UV curable adhesive composition that develops an adhesive force by a polymerization reaction caused by irradiation with ultraviolet rays or the like is different from a solvent-type adhesive that manifests an adhesive force when the solvent is volatilized by heating. Since generation of VOC (Volatile Organic Compound) is suppressed, it is advantageous from the viewpoint of work environment and safety (see JP 2006-282805 A).

  In recent years, it has become possible to form a pattern with a small line width with high accuracy by improving the accuracy of a printing press, improving a printing plate, etc., and its use is being expanded. As a pressure-sensitive adhesive composition used in such screen printing and coated on a base material, an ultraviolet curing type that can suppress the generation of VOC and does not require a drying step is suitable, and has a wide range. Various studies have been made on the adherend to improve the adhesiveness (see JP 2013-216742 A).

JP 2006-282805 A JP 2013-216742 A

  However, in applications such as stickers, labels, and laminates for household appliances, such as bonding to recyclable components, the UV curable adhesive composition not only has good adhesion to the adherend. In addition, it is necessary that the adhesive residue at the time of peeling is suppressed, and furthermore, in order to enable a fine shape, the film thickness in screen printing can be made more appropriate and the surface smoothness is excellent. Further, it is required that the protrusion from the screen frame is suppressed and the screen printability is excellent.

  The present invention has been made on the basis of the circumstances as described above, and an object thereof is an ultraviolet curable pressure-sensitive adhesive that has a low VOC and can achieve good screen printability and good adhesiveness in a balanced manner. It is to provide a composition.

  The invention made in order to solve the above-mentioned problems includes (A) a reactive polymer, (B) a photopolymerization initiator, (C) a monomer having a polymerizable double bond, and (D) a silicone-based polymer. The compound (A) contains a repeating unit derived from a (meth) acrylic monomer, and has a functional group containing a (meth) acryloyl skeleton from 0.3 mmol / 100 g to 40 mmol / 100 g. The weight average molecular weight is 100,000 or more and 500,000 or less, the glass transition temperature is −55 ° C. or more and 0 ° C. or less, and the component (B) is 2-hydroxy-1- {4- [4- ( It is an ultraviolet curable pressure-sensitive adhesive composition containing 2-hydroxy-2-methyl-propionyl) -benzyl] -phenyl} -2-methyl-propan-1-one.

  In the ultraviolet curable pressure-sensitive adhesive composition, the content of the component (B) is 5 parts by mass to 25 parts by mass with respect to 100 parts by mass of the component (A), and the content of the component (C) is 200. It is preferable that the content of the component (D) is 2 parts by mass or more and 8 parts by mass or less.

  The ultraviolet curable pressure-sensitive adhesive composition of the present invention has a low VOC and can achieve good screen printability and good adhesiveness in a well-balanced manner.

  Hereinafter, preferred embodiments according to the present invention will be described in detail. It should be understood that the present invention is not limited only to the embodiments described below, and includes various modifications that are implemented within a scope that does not change the gist of the present invention. In addition, “˜ (meth) acrylate” in the present specification is a concept encompassing both “˜acrylate” and “˜methacrylate”. “(Meth) acrylic acid” is a concept encompassing both “acrylic acid” and “methacrylic acid”. “(Meth) acryloyl” is a concept encompassing both “acryloyl” and “methacryloyl”.

<Ultraviolet curing adhesive composition>
The ultraviolet curable pressure-sensitive adhesive composition contains (A) a reactive polymer, (B) a photopolymerization initiator, (C) a monomer having a polymerizable double bond, and (D) a silicone compound.
Hereinafter, each component contained in the ultraviolet curable adhesive composition according to the present embodiment will be described.

[(A) Reactive polymer]
(A) The reactive polymer (hereinafter also referred to as “component A”) contains a repeating unit derived from a (meth) acrylic monomer, and has a functional group containing a (meth) acryloyl skeleton in an amount of 0.3 mmol / 100 g or more. 40 mmol / 100 g or less, a weight average molecular weight of 100,000 or more and 500,000 or less, and a glass transition temperature of −55 ° C. or more and 0 ° C. or less.

(Repeating unit derived from (meth) acrylic monomer)
A component contains the repeating unit derived from a (meth) acrylic-type monomer. By including a repeating unit derived from a (meth) acrylic monomer, an ultraviolet curable pressure-sensitive adhesive composition having excellent adhesiveness can be produced. Moreover, it is preferable that A component contains the repeating unit derived from a (meth) acrylic-type monomer in a principal chain. In the present specification, the “main chain” means a carbon chain having the largest number of carbon atoms in the component A.

  The (meth) acrylic monomer means acrylic acid, methacrylic acid or derivatives thereof. Specifically, in addition to acrylic acid and methacrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, i-propyl (meth) acrylate, n-butyl (meth) acrylate, i -Butyl (meth) acrylate, t-butyl (meth) acrylate, n-pentyl (meth) acrylate, i-pentyl (meth) acrylate, n-hexyl (meth) acrylate, n-octyl (meth) acrylate, 2- (Meth) acrylic acid esters such as ethylhexyl (meth) acrylate, lauryl (meth) acrylate, cyclohexyl (meth) acrylate; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxy Propyl (meth) acrylate, etc. Hydroxyl group-containing (meth) acrylates; (meth) acrylates such as ammonium (meth) acrylate, sodium (meth) acrylate, potassium (meth) acrylate; (meth) acrylamides such as (meth) acrylamide And (meth) acrylonitriles such as (meth) acrylonitrile.

  Component A may contain one or more repeating units derived from a (meth) acrylic monomer, and in addition to the repeating unit derived from a (meth) acrylic monomer, ) It can contain repeating units derived from other monomers other than acrylic monomers. A component may be a homopolymer containing only a repeating unit derived from one (meth) acrylic monomer, but contains a repeating unit derived from two or more (meth) acrylic monomers. A copolymer or a copolymer containing a repeating unit derived from another monomer other than the (meth) acrylic monomer is preferred.

  As the monomer other than the (meth) acrylic monomer, for example, a monomer having a polymerizable unsaturated bond-containing group other than the (meth) acryloyl group can be used. Specifically, aromatic vinyl compounds such as styrene and α-methylstyrene; carboxylic acid vinyl esters such as vinyl acetate and vinyl propionate, unsaturated dicarboxylic acids such as maleic anhydride, itaconic acid and fumaric acid, or the like Anhydrides; N-vinyl lactams such as N-vinyl pyrrolidone and N-vinyl caprolactam can be exemplified.

  As a minimum of the content rate of the repeating unit derived from a (meth) acrylic monomer with respect to a total of 100 parts by mass of the repeating units derived from the monomer constituting the component A, 50 parts by mass is preferable, and 90 parts by mass. Is more preferable, and it is more preferable that all of the main chain is composed of repeating units derived from a (meth) acrylic monomer.

(Functional group containing (meth) acryloyl skeleton)
The A component has a functional group containing a (meth) acryloyl skeleton. The component A preferably has a functional group containing a (meth) acryloyl skeleton in the side chain. In the present specification, the “side chain” means a carbon chain branched from the main chain of the component A.

  In the ultraviolet curable pressure-sensitive adhesive composition, since the component A has a functional group containing a (meth) acryloyl skeleton, the polymers are cross-linked by irradiation with ultraviolet rays, and therefore, ultraviolet curable properties are exhibited. Moreover, in addition to high adhesiveness, when the adhesive is peeled off, there is little adhesive residue on the adherend, and a preferable effect of hardly contaminating the adherend is exhibited.

  Examples of the functional group containing a (meth) acryloyl skeleton include an acryloyl group and a methacryloyl group. An acryloyl group is preferable in that it can provide excellent polymerizability, and consequently ultraviolet curability, and a methacryloyl group is preferable in terms of higher safety compared to an acryloyl group.

  In addition, the functional group including the (meth) acryloyl skeleton does not need to have a structure in which the acryloyl skeleton or the methacryloyl skeleton is directly bonded to the main chain, and the acryloyl skeleton or the methacryloyl skeleton is indirectly connected via another atom or a functional group. In particular, the structure may be bonded to the main chain, and examples thereof include a (meth) acryloyloxy group.

  The lower limit of the content of the functional group containing the (meth) acryloyl skeleton in 100 g of component A is 0.3 mmol, and preferably 0.5 mmol. The upper limit of the content is 40 mmol, preferably 20 mmol. For example, when the weight average molecular weight of the component A is 300,000, the lower limit of the number of functional groups containing a (meth) acryloyl skeleton per molecule of the polymer is preferably 0.9, and 1.5 More preferred. On the other hand, the upper limit of the number is preferably 120, and more preferably 60.

  When the content of the functional group containing the (meth) acryloyl skeleton is less than the lower limit, effects such as ultraviolet curing of the component A, adhesiveness, and less adhesive residue on the adherend may not be obtained sufficiently. is there. On the other hand, when the upper limit is exceeded, the adhesive strength is reduced, and the storage stability of the ultraviolet curable adhesive composition may be deteriorated.

(Weight average molecular weight)
The lower limit of the weight average molecular weight (Mw) of the component A is 100,000, preferably 150,000. The upper limit of the Mw is 500,000, preferably 350,000. By making Mw within the above range, the solubility and miscibility of the component A with respect to the monomer having a polymerizable double bond (C) is improved, and the preparation of the ultraviolet curable pressure-sensitive adhesive composition is facilitated. The adhesive residue at the time of peeling can be further suppressed.

  The Mw of the component A can be controlled by the polymerization initiator, the chain transfer agent and the type and amount of the solvent used when polymerizing the (meth) acrylic monomer, the reaction temperature, the reaction time, and the like. Moreover, you may select suitably what has a desired weight average molecular weight from commercially available (meth) acrylic-type polymers, and synthesize | combine A component using this.

Mw of A component in this specification is a value measured using the gel permeation chromatography (GPC) by the following conditions.
GPC column: For example, two “TSKgel-Multipore H _XL- M” manufactured by Tosoh Corporation Column temperature: 40 ° C.
Elution solvent: Tetrahydrofuran (Wako Pure Chemical Industries)
Flow rate: 1.0 mL / min Sample concentration: 0.05% by mass
Sample injection volume: 100 μL
Detector: Differential refractometer Standard material: Monodisperse polystyrene

(Glass-transition temperature)
As a minimum of the glass transition temperature (Tg) of A component, it is -55 degreeC and -35 degreeC is preferable. The upper limit of the Tg is 0 ° C, and -5 ° C is preferable. When Tg exceeds the upper limit, the adhesive strength of the ultraviolet curable adhesive composition tends to decrease. If Tg is less than the lower limit, the adhesive residue at the time of peeling tends to increase.

The Tg of the component A can be controlled based on known knowledge by the type and content ratio of the repeating unit derived from the (meth) acrylic monomer.
In the present specification, “glass transition temperature” means a glass transition temperature measured in accordance with JIS K7121 (plastic transition temperature measurement method).

  As a minimum of content of A ingredient in the ultraviolet curing type adhesive constituent concerned, 5 mass% is preferred and 10 mass% is preferred. As an upper limit of the said content, 80 mass% is preferable and 50 mass% is more preferable.

(Method for producing component A)
Although the manufacturing method of A component is not specifically limited, For example, it manufactures by the method (chemical modification method) which introduce | transduces the functional group containing (meth) acryloyl frame | skeleton by chemical modification with respect to the (meth) acrylic-type polymer used as a basic skeleton. can do. Specifically, it can be produced by the method described in JP-A-2006-282805.

[(B) Photopolymerization initiator]
(B) The photopolymerization initiator (hereinafter also referred to as “B component”) is a substance that causes a polymerization reaction upon irradiation with light in the ultraviolet curable pressure-sensitive adhesive composition.

  Examples of the B component include α-hydroxyacetophenone (“Irgacure 184” from BASF), 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] -phenyl} -2 -Methyl-propan-1-one ("Irgacure 127" from BASF), α-aminoacetophenone, benzoin compounds, acylphosphine oxide compounds (for example, "Irgacure 819" from BASF, "Irgacure TPO" from BASF, etc.), etc. Can be used.

  Among these, the ultraviolet curable pressure-sensitive adhesive composition is 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] -phenyl} -2-methyl-propane. -1-one (hereinafter also referred to as “B1 component”) is contained as an essential component. When B1 component is contained, the ultraviolet curable property in the air of the ultraviolet curable pressure-sensitive adhesive composition is improved, and preferable effects of improving adhesive force and reducing adhesive residue are exhibited.

  As a minimum of content of B ingredient, 5 mass parts are preferred to 100 mass parts of A ingredient, and 10 mass parts are more preferred. As an upper limit of the said content, 25 mass parts is preferable and 20 mass parts is more preferable. When the content of the B component is within the above range, it can more effectively act as a photopolymerization initiator, and can further be suppressed from remaining excessively after irradiation with ultraviolet rays and deteriorating adhesive properties.

  As a minimum of the content rate of B1 component in B component, 20 mass% is preferable and 40 mass% is more preferable. As an upper limit of the said content rate, 80 mass% is preferable and 60 mass% is more preferable.

[(C) Monomer having polymerizable double bond]
(C) A monomer having a polymerizable double bond (hereinafter also referred to as “C component”) has a polymerizable double bond such as a vinyl group or a (meth) acryloyl group, and is polymerized by irradiation with ultraviolet rays. There are no particular restrictions on the type of monomers that can be used. When the ultraviolet curable pressure-sensitive adhesive composition contains the component C, the viscosity of the ultraviolet curable pressure-sensitive adhesive composition is excellent with respect to screen printing, and the adhesive strength after ultraviolet irradiation is excellent.

  As C component, for example, acrylic acid, methacrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, i-propyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, t-butyl (meth) acrylate, n-pentyl (meth) acrylate, i-pentyl (meth) acrylate, n-hexyl (meth) acrylate, n-octyl (meth) acrylate, 2 -Ethylhexyl (meth) acrylate, lauryl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, tetrahydrofurfuryl alcohol acrylic acid multimer ester, ethoxyethoxyethanol acrylic acid multimer ester ( T) Acrylic acid esters; hydroxyl-containing (meth) acrylic acid esters such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 4-hydroxybutyl acrylate Polyfunctional (meth) acrylates such as 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate; Examples thereof include carboxylic acid vinyl esters such as vinyl acetate and vinyl propionate; aromatic vinyl compounds such as styrene and α-methylstyrene.

  As a minimum of content of C component, 200 mass parts is preferred to 250 mass parts with respect to 100 mass parts of A component. As an upper limit of the said content, 400 mass parts is preferable and 350 mass parts is more preferable. By making content of C component into the said range, while the viscosity of an ultraviolet curable adhesive composition becomes a more favorable thing with respect to screen printing, adhesive force improves more.

[(D) Silicone compound]
(D) By containing a silicone compound (hereinafter also referred to as “D component”), the components are mixed and stirred by the defoaming action of the D component to produce the ultraviolet curable pressure-sensitive adhesive composition. It is possible to greatly reduce the mixing of bubbles into the composition. In addition, since the generation of bubbles can be reduced even when the obtained ultraviolet curable pressure-sensitive adhesive composition is applied, a uniform pressure-sensitive adhesive surface can be obtained. Furthermore, it is thought that the fluidity | liquidity of an ultraviolet curable adhesive composition can be improved by containing D component, and a homogeneous adhesive layer can be produced by screen printing. Further, the heat stability of the ultraviolet curable pressure-sensitive adhesive composition is improved by the thermal stability of the D component, and the surface energy of the pressure-sensitive adhesive is reduced, so that a preferable effect of reducing the adhesive residue at the time of peeling is exhibited.

  Examples of the D component include silicone-based compounds having, for example, polysiloxane, dimethylpolysiloxane, diphenylpolysiloxane, methylphenylpolysiloxane, methylvinylpolysiloxane, etc. as main constituents of the defoaming effect; hydrophobic silica based on silicone, etc. An oil compound type silicone compound that is blended and used as a main component of the defoaming effect; a mineral oil type compound in which hydrophobic silica, amide, silicone, fatty acid and the like are blended based on mineral oil can be exemplified.

  Among the compounds, oil compound type silicone compounds are preferable in that the fluidity is more suitable for screen printing and the adhesive residue at the time of peeling is further reduced.

  Specific examples of commercially available products containing component D include, for example, KS-66 (Shin-Etsu Chemical Co., Ltd.), KS-69 (Shin-Etsu Chemical Co., Ltd.), DK Q1-049 (Toray Dow Corning Co., Ltd.), and SH5500 COMPOUND (Toray Dow). Corning), SC5540 COMPOUND (Toray Dow Corning), 8590ADDITIVE (Toray Dow Corning), TSA750 (Momentive Performance Materials), TSA750S (Momentive Performance Materials), and the like.

  As a minimum of content of D ingredient, 2 mass parts is preferred to 100 mass parts of A ingredient, and 3 mass parts is more preferred. As an upper limit of the said content, 8 mass parts is preferable and 6 mass parts is more preferable. When the content of component D is in the above range, the fluidity of the ultraviolet curable pressure-sensitive adhesive composition becomes optimal, and a more uniform pressure-sensitive adhesive layer can be produced by screen printing, resulting in optimal adhesive strength. At the same time, the adhesive residue at the time of peeling can be further reduced.

[Optional ingredients]
The ultraviolet curable pressure-sensitive adhesive composition may contain other additives as optional components in addition to the components A to D. Other additives include, for example, UV absorbers, tackifiers, antioxidants, anti-aging agents, colorants, light stabilizers, coupling agents, thermal polymerization inhibitors, leveling agents, surfactants, and storage stability. Known additives that may be blended in the pressure-sensitive adhesive composition, such as an agent, a plasticizer, and a filler, can be mentioned.
As such known additives, for example, the additives described in JP-A-2006-282805 can be used.
When the ultraviolet curable pressure-sensitive adhesive composition contains an optional component, the content thereof can be appropriately selected within a range not impairing the effect of the ultraviolet curable pressure-sensitive adhesive composition. Usually, it is 5 parts by mass or less.

[Method for preparing UV-curable adhesive composition]
The ultraviolet curable pressure-sensitive adhesive composition can be prepared, for example, by mixing A to D components and optional components contained as necessary at a predetermined ratio.

  As a minimum of the viscosity in 25 degreeC of the said ultraviolet curable adhesive composition, 2,000 mPa * s is preferable and 4,000 mPa * s is more preferable. The upper limit of the viscosity is preferably 12,000 mPa · s, more preferably 8,000 mPa · s. When the viscosity is in the above range, the film thickness at the time of screen printing becomes more appropriate, and the protrusion from the screen frame is further suppressed, and more appropriate for screen printing is given. The viscosity is a value measured using a BM viscometer under the condition of a rotational speed of 6 rpm.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to these Examples.

<Synthesis of component A>
(A) A reactive polymer was synthesized according to the following method.
Each monomer used for the synthesis of component A is shown below.
EA: Ethyl acrylate (Toagosei)
BA: Butyl acrylate (Wako Pure Chemical Industries, Ltd.)
2EHA: 2-ethylhexyl acrylate (Toagosei Co., Ltd.)
AN: Acrylonitrile (Showa Denko)
HEMA: 2-hydroxyethyl methacrylate (Osaka Organic Chemical Co., Ltd.)

[Synthesis Example 1]
In a four-necked flask, 56 parts by mass of EA as a monomer, 27 parts by mass of BA, 10 parts by mass of AN and 7 parts by mass of HEMA, 2 parts by mass of AIBN as a radical polymerization initiator and 150 parts by mass of ethyl acetate as a solvent were charged. The solution containing (meth) acrylic polymer (a-1) was obtained by reacting at 70 ° C. for 8 hours and further at 80 ° C. for 1 hour. Next, a solution containing 100 parts by mass (resin solid content) of this (meth) acrylic polymer (a-1) in a four-necked round bottom flask equipped with a cooler and a thermometer, and dibutyltin laurate as a reaction catalyst 0.01 parts by mass was charged and heated to 40 ° C. with stirring. Subsequently, 0.5 part by mass of 2-methacryloyloxyethyl isocyanate (“Karenz MOI” (hereinafter also referred to as “MOI”) manufactured by Showa Denko KK) was added, and the reaction was performed at 40 ° C. for 5 hours. Thereby, the hydroxyl group in (meth) acrylic-type polymer (a-1) and the isocyanate group in MOI couple | bond together, and the solution containing the reactive polymer which has a functional group containing a (meth) acryloyl skeleton in a side chain Got. Subsequently, ethyl acetate was removed out of the system, and the residual solvent was adjusted to 1% by mass or less to obtain a reactive polymer (A-1). Mw of (A-1) was 250,000, Tg was −7 ° C., and the content of the functional group containing the (meth) acryloyl skeleton was 3.2 mmol per 100 g of the reactive polymer (A-1).

[Synthesis Examples 2 to 12]
The same manner as in Synthesis Example 1 except that the types and amounts of monomers shown in Table 1 below were used and the content of the functional group containing Mw and (meth) acryloyl skeleton was the values shown in Table 1. Thus, reactive polymers (A-2) to (A-12) were obtained. “-” In Table 1 indicates that the corresponding monomer was not used.

<Preparation of UV-curable adhesive composition>
Using the components A ((A-1) to (A-12)) synthesized in Synthesis Examples 1 to 12, ultraviolet curable pressure-sensitive adhesive compositions were prepared. It shows below about each component other than A component used for preparation of an ultraviolet curable adhesive composition.

[[B] Photopolymerization initiator]
B-1: 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] -phenyl} -2-methyl-propan-1-one ("Irgacure 127" from BASF) )
B-2: 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (“Irgacure TPO” from BASF)
B-3: 1-hydroxy-cyclohexyl phenyl ketone ("Irgacure 184" from BASF)

[(C) Monomer having polymerizable double bond]
C-1: Acrylic acid multimeric ester of tetrahydrofurfuryl alcohol (“Biscoat # 150D” from Osaka Organic Chemical Industry Co., Ltd.)
C-2: Isobornyl acrylate (“IBXA” from Osaka Organic Chemical Industry Co., Ltd.)
C-3: 4-hydroxybutyl acrylate (“4-HBA” from Osaka Organic Chemical Industry Co., Ltd.)
C-4: 1,6-hexanediol diacrylate (“Kyoeisha Chemical Co., Ltd.“ Light acrylate 1.6HX-A ”)

[(D) Silicone compound]
D-1: DK Q1-049 (Toray Dow Corning)
D-2: KF-96 (Shin-Etsu Chemical Co., Ltd.)

[Non-silicone compounds]
d-1: BYK-052 (Big Chemie Japan)
d-2: Florene AC-2300C (Kyoeisha Chemical Company)

[(E) Antioxidant]
E-1: Irganox 1035 (BASF)

[Example 1]
(A) (A-1) 100 parts by mass as a reactive polymer, (B) 8 parts by mass and (B-2) 8 parts by mass as a photopolymerization initiator, (C) Polymerizability (C-1) 240 parts by mass, (C-2) 70 parts by mass, (C-3) 7 parts by mass and (C-4) 8 parts by mass as a monomer having a double bond, (D) silicone 4 parts by mass of (D-1) as a system compound and 2 parts by mass of (E-1) as an antioxidant (E) were mixed to prepare an ultraviolet curable pressure-sensitive adhesive composition (T-1). The viscosity of the obtained (T-1) was 5,000 mPa · s.

[Examples 2 to 12 and Comparative Examples 1 to 10]
Except having used each component of the kind and content shown in following Table 2, it was carried out similarly to Example 1, and ultraviolet curable adhesive composition (T-2)-(T-12) and (CT-1). ~ (CT-10) was prepared. In Comparative Examples 8 to 10, (D) a silicone compound was not contained, and instead, in Comparative Examples 9 and 10, a non-silicone compound (d-1 or d-2) was used.

<Evaluation>
About the prepared ultraviolet curable adhesive composition, the following item was evaluated in accordance with the following method. The evaluation results are shown in Table 2 below.

[Screen printability]
About the obtained ultraviolet curable adhesive composition, screen printability was evaluated using the screen printer ("HK320" of SERIA). The screen printing plate uses a patterned polyester mesh plate (Tetron # 120 mesh, wire diameter 54 μm, aperture ratio 55%, Tokai Shoji Co., Ltd.), and a 100 μm thick polyethylene terephthalate (PET) film (Toyobo Cosmo Shine 4300 ") was printed with a pattern and irradiated with ultraviolet rays (light source: metal halide lamp, illuminance: 300 mW / cm ² , integrated light quantity 400 mJ / cm ² ) under air to cure the printed matter. The cured printed matter was visually observed for film thickness, surface smoothness, and the presence or absence of protrusion from the screen frame.

  The film thickness is measured with a film thickness meter. When the film thickness is 40 μm or more and 70 μm or less, “◯” (good), and when it is 25 μm or more but less than 40 μm or more than 70 μm and 85 μm or less, “△” (somewhat good). ) And less than 25 μm or exceeding 85 μm, it was evaluated as “x” (bad). As for the smoothness of the surface, the surface of the printed surface is visually observed. When smooth, “◯” (good), when slight irregularities are seen, “△” (slightly good), mesh marks and When bubbles were observed, it was evaluated as “x” (poor). As for the protrusion from the screen frame, the edge of the printed product is visually observed. When the protrusion from the screen frame is less than 1 mm, “◯” (good), and when it is 1 mm or more and less than 2 mm, “△” (slightly good) ) And 2 mm or more, it was evaluated as “x” (defect).

[Initial tack]
The tackiness of the obtained ultraviolet curable pressure-sensitive adhesive composition was evaluated by the following method. Specifically, 50 g of the UV curable pressure-sensitive adhesive composition to be evaluated was used as it was as a coating solution, and applied to the surface of a polyethylene terephthalate (PET) film (“Cosmo Shine 4300” manufactured by Toyobo Co., Ltd.) using an applicator. By irradiating ultraviolet rays having a wavelength of 200 to 400 nm with a high-pressure mercury lamp and curing the ultraviolet rays, a coating film (adhesive layer) having a thickness of 50 μm was formed on the surface of the PET film. Thereafter, the PET film having the pressure-sensitive adhesive layer was bonded to alkali glass (trade name: general hard glass) to form a laminate. 180 degree of adhesive strength of PET film and alkali glass after leaving this laminated body for 30 minutes by a normal state (temperature: 23 degreeC, humidity: 50%) as described in JISZ0237 (adhesive tape * adhesive sheet test method). Measured by peel test. Further, the adhesive residue on the surface of the alkali glass was evaluated visually.

  Regarding the initial adhesiveness, the adhesive strength was evaluated as “◯” (good) when the measured value of the 180 ° peel test was 3 N / 25 mm or more, and “X” (bad) when it was less than 3 N / 25 mm. Regarding the adhesive residue, “○” (good) when no adhesive residue is visually observed, and “△” (slightly good) when very little adhesive residue is visually observed, the peeled portion visually. When adhesive residue was observed on the entire surface of the film, it was evaluated as “x” (defective).

[Heat-resistant]
A “test piece bonded to an alkali glass adherend” produced by the same method as in the section of “Initial tackiness” was heated at 60 ° C. for 24 hours. After heating, it was allowed to stand for 30 minutes in a normal state, a 180 ° peel test in accordance with JIS Z0237 was performed, and the adhesive residue on the alkali glass was visually confirmed. For heat resistance, “○” (good) when no adhesive residue is visually observed, and “△” (slightly good) when very little adhesive residue is visually observed, visually peeled part When adhesive residue was observed on the entire surface of the film, it was evaluated as “x” (defective).

  The ultraviolet curable pressure-sensitive adhesive composition of Example 1 showed good results in both screen printability, initial tackiness, and heat resistance. The ultraviolet curable adhesive compositions of Examples 2 to 8 showed the same results as those of Example 1. Although the ultraviolet curable adhesive composition of Examples 9-12 compared with the thing of Example 1 and a slight adhesive residue was recognized at the time of a heat-resistant print, the initial stage adhesiveness of Example 1 The result was equivalent to the above. In Comparative Examples 1 to 10, a decrease in adhesive strength and poor adhesive residue were observed in the initial adhesiveness. In addition, defects were observed in either screen printability and / or heat resistance.

  The ultraviolet curable pressure-sensitive adhesive composition of the present invention is excellent in screen printability and nonpolar with glass and other materials than glass, for example, a polar resin material (PET, ABS, etc.) or corona discharge treatment. The resin material (PE, PP, etc.) also shows good adhesiveness and peels without any adhesive residue even at the time of peeling, so the glass material and these resin materials, or a seal that bonds the resin materials together, label use, It can use suitably for uses, such as member bonding in household appliances in which a fine pattern is required.

Claims (2)

(A) a reactive polymer;
(B) a photopolymerization initiator;
(C) a monomer having a polymerizable double bond;
(D) a silicone compound and
The component (A) is
Including repeating units derived from (meth) acrylic monomers,
Having a functional group containing a (meth) acryloyl skeleton from 0.3 mmol / 100 g to 40 mmol / 100 g,
The weight average molecular weight is 100,000 or more and 500,000 or less,
The glass transition temperature is −55 ° C. or more and 0 ° C. or less,
As the component (B),
An ultraviolet curable pressure-sensitive adhesive composition containing 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] -phenyl} -2-methyl-propan-1-one.   The content of the component (B) is 5 parts by mass to 25 parts by mass with respect to 100 parts by mass of the component (A), the content of the component (C) is 200 parts by mass to 400 parts by mass, The ultraviolet curable pressure-sensitive adhesive composition according to claim 1, wherein the content of component D) is 2 parts by mass or more and 8 parts by mass or less.