JPH05163470A - Alkaline water-soluble tacky agent composition - Google Patents

Abstract

PURPOSE:To obtain an alkaline water-soluble tacky agent composition insoluble in acidic and neutral water, soluble only in ''the alkaline water, hardly causing an adhesion accelerating phenomenon with time and excellent in removability after application for a long period or under high temperature and humidity conditions. CONSTITUTION:An alkaline water-soluble tacky agent composition is obtained by blending 100 pts.wt. alkaline water-soluble tacky agent, soluble only in alkaline water and insoluble in acidic and neutral water with a water-dispersible or a water-soluble silicone-based surfactant in an amount within the range of <=10 pts.wt.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an alkaline water-soluble pressure-sensitive adhesive composition, and more particularly to a pH that dissolves in alkaline water
The present invention relates to an alkaline water-soluble pressure-sensitive adhesive composition which has selectivity, can be washed with water in the field of electronic materials, and has excellent adhesiveness and removability.

[0002]

BACKGROUND OF THE INVENTION Water-soluble pressure-sensitive adhesives have a long history, and rewet type adhesives using a natural product-based water-soluble polymer such as sugar, protein or rubber are well known. As the base polymer, gum arabic, dextrin, starch, glue or the like is used. These tacky materials do not normally have tackiness, but are activated by water and show tackiness. Then, after being adhered to the adherend, these adhesive materials exhibit an adhesive force by being dried.
Therefore, these adhesive materials are widely used for postage stamps, stamps, bran paper, etc. because they can be used only by wetting them with water, are not unsanitary, and are inexpensive.

On the other hand, a water-soluble adhesive having tackiness in a normal state is especially used in the papermaking industry by fixing paper and paper with a water-soluble adhesive.
It is widely used for the purpose of returning the bonded portion to the pulp dissolving tank for reuse after splicing. Further, it is also used as a pressure-sensitive adhesive for labels such as bottles and foods, particularly a pressure-sensitive adhesive for labels that makes it possible to easily remove the label by washing with water when it is no longer needed. Further, in the field of sanitary napkins, it is used as a pressure-sensitive adhesive for fixation, and the pressure-sensitive adhesive component remaining on underwear is easily washed and removed by washing.

As the water-soluble pressure-sensitive adhesive as described above, as disclosed in JP-A-60-229972, 100 parts by weight of polyacrylic acid, 70 parts by weight of diethylene glycol and 50 parts by weight of polypropylene glycol are blended, Polyacrylic acid obtained by neutralizing a part of carboxyl groups with potassium, and as disclosed in JP-B-52-32769, 100 parts by weight of polyethyleneimine, 30 parts by weight of aminated and phosphorylated starch, and polyacryl. Those containing 7.5 parts by weight of an acid are known.

In the field of electronic materials, a protective tape is attached to protect printed circuit boards, semiconductors, etc., the protective tape is peeled off before assembly, and the remaining adhesive residue for the protective tape is flon. It was removed by washing with a solvent such as. However, in recent years, in order to protect the global environment, it has been required to wash with water instead of CFCs, and therefore, as an adhesive for a protective tape, it is required that the adhesive component residue can be washed with water. There is.

As an example of the above-mentioned protective tape, a plating masking tape for a printed circuit board or the like has been widely used. This plating masking tape for a printed circuit board is used when gold plating the terminal portion, and is a protective member that is indispensable in the production process of the printed circuit board. In the plating step, a strongly acidic plating solution or a plating pretreatment solution is used. Therefore, as an adhesive for a plating masking tape on a printed circuit board, a water-repellent or water-insoluble adhesive is used in order to prevent the adhesive from being dissolved or swollen by a plating solution or a plating pretreatment solution, or from being reduced in adhesiveness. Adhesives have been used.

However, as described above, in the field of electronic materials, there is a demand for cleaning with water instead of CFCs,
Also in the plating masking tape, it is required that the adhesive residue can be washed with water after peeling. Further, when mechanically polishing a semiconductor chip, it is necessary to switch the fixing adhesive for fixing the chip to one that can withstand the water washing step instead of the conventional CFC washing step. However, since water is sprayed on the polishing surface in the mechanical polishing step, a water-soluble pressure-sensitive adhesive whose adhesive strength is easily reduced by water is not suitable.

As described above, in the process of plating a printed circuit board, the process of manufacturing a semiconductor component, etc., the component is fixed by temporary adhesion, or is used as a mask for processing only a necessary portion. There is a demand for a water-soluble pressure-sensitive adhesive that is soluble only in alkaline water.

[0009]

However, in the conventional water-soluble pressure-sensitive adhesives, the base polymer has a high polarity as disclosed in JP-A-1-165685, and when it is stuck for a long time, the adherend is re-peeled. There is a possibility that a so-called adhesion promotion phenomenon may occur such that the tacky component remains on the upper surface, the adhesive force increases with time, and re-peeling becomes impossible.

Therefore, the object of the present invention is to solve the above-mentioned drawbacks of the conventional water-soluble pressure-sensitive adhesives, are insoluble in acidic water and neutral water, dissolve only in alkaline water, and wash with the alkaline water. It is an object of the present invention to provide a water-soluble pressure-sensitive adhesive composition that can be produced, is less likely to cause an adhesion promotion phenomenon, and is excellent in removability after use for a long time or under high temperature and high humidity.

[0011]

Means for Solving the Problems The present inventors have found that the pH is insoluble in acidic water and neutral water, is soluble only in alkaline water, and can be washed and removed by the alkaline water.
In a water-soluble pressure-sensitive adhesive having selectivity, as a result of diligent studies to suppress the above-mentioned phenomenon of adhesion promotion and to give excellent removability, a specific silicone-based surfactant was added to the pH-selective water-soluble pressure-sensitive adhesive. It has been found that the above-mentioned problems can be achieved by blending, and the present invention has been completed.

That is, according to the present invention, 100 parts by weight of a water-soluble pressure-sensitive adhesive which is insoluble in acidic water and neutral water and soluble only in alkaline water is water-dispersible having a polyalkylene oxide chain in the molecule or A water-soluble pressure-sensitive adhesive composition comprising a water-soluble silicone surfactant in a proportion of 10 parts by weight or less. Hereinafter, the constitution of the water-soluble pressure-sensitive adhesive composition of the present invention will be described in detail.

Since the pressure-sensitive adhesive composition of the present invention contains as a main component a water-soluble pressure-sensitive adhesive which is insoluble in acidic water and neutral water and is soluble only in alkaline water, it is pH-selective soluble only in alkaline water. It has water solubility. Further, since the water-dispersible or water-soluble silicone-based surfactant is blended, the adhesion promotion phenomenon that occurs during adhesion to an adherend under a long-term or high-temperature and high-humidity condition is suppressed, and re-peeling Sometimes the adhesive itself remains on the adherend,
The so-called adhesive residue phenomenon is prevented.

As the water-dispersible or water-soluble silicone surfactant, a surfactant having a polydialkylsiloxane chain as a hydrophobic group and a polyalkylene oxide chain as a hydrophilic group in the same molecule in any combination is used. can do. The chain length, sequence and structure of the polydialkylsiloxane chain and the polyalkylene oxide chain are not particularly limited, but it is preferable that the surfactant itself has water solubility or water solubility that selectively dissolves only in alkaline water. Furthermore, an amino group in the molecule,
It may have a portion modified with a hydroxyl group, a carboxyl group, an epoxy group or the like. The molecular weight of the surfactant is not particularly limited, but it is preferable that the total molecular weight of the surfactant is 10,000 or less because the effect of imparting removability becomes large.

Specific examples of the above silicone-based surfactant include 1,5-bis (methoxytriethylene glycol) -1,1,3,3,5,5-hexamethyltrisiloxane, α, ω- Bis (polyethylene glycol) polydimethyl siloxane, or Nippon Unicar, trade name: SILWET L-7602, SILWET FZ
-2164, SILWET FZ-2120, etc. are mentioned, At least 1 sort (s) can be selected and used for these.

The above-mentioned silicone-based surfactant is added to 100 parts by weight of a water-soluble adhesive which is soluble only in alkaline water.
It is mixed in an amount of 10 parts by weight or less, preferably 5 parts by weight or less. When the blending ratio of the above-mentioned surfactant exceeds 10 parts by weight, the water solubility which is selectively dissolved only in alkaline water is impaired, and it becomes soluble in acidic water and neutral water as well.
In addition, since the cohesiveness of the pressure-sensitive adhesive is impaired, the shear adhesive force is reduced, and further, the excessive bleeding out of the surfactant at the adhesive interface significantly reduces the initial adhesive force. The water-soluble adhesive which does not dissolve in the acidic water and neutral water, but dissolves only in alkaline water is not particularly limited, and examples thereof include a carboxyl group-containing acrylic type, vinyl acetate-Poval type, carboxyl group-modified Poval type, and aceto group. An appropriate adhesive such as an acetylated Poval type can be used.

The water-soluble pressure-sensitive adhesive composition of the present invention has the above p
Water-soluble adhesive showing H-selectivity and water-dispersible or water-soluble silicone surfactant, as well as cross-linking agent, plasticizer, tackifier, anti-aging agent, stabilizer, neutralizing agent, filling Agents and the like can be appropriately blended as long as the object of the present invention can be achieved.

The water-soluble pressure-sensitive adhesive composition of the present invention can be used alone or by processing it as a pressure-sensitive adhesive tape or sheet. However, the method of using the water-soluble pressure-sensitive adhesive composition of the present invention is not limited to the above. Further, in the case of processing into a pressure-sensitive adhesive tape or pressure-sensitive adhesive sheet, the water-soluble pressure-sensitive adhesive composition of the present invention can be uniformly applied and used on a support such as a flexible plastic film, paper or cloth. In this case, the coating thickness of the water-soluble pressure-sensitive adhesive composition is usually 20 to 2
It is set to about 00 μm.

[0019]

In the present invention, the water-soluble pressure-sensitive adhesive having the above-mentioned pH selectivity is blended with the above-mentioned specific water-dispersible or water-soluble silicone surfactant in the above-mentioned specific ratio. This silicone-based surfactant bleeds out moderately to the adhesive interface with the adherend within the range of the above-mentioned specific ratio, and the polar group in the polymer of the water-soluble adhesive and the polar group on the adherend interface are Acts to mitigate the interaction of. Therefore, the action of the water-soluble silicone-based surfactant suppresses the so-called adhesion promotion phenomenon that increases the adhesive force over time, and when processed into a pressure-sensitive adhesive tape or sheet, it can be used for a long time or under high temperature and high humidity. It shows excellent removability even after being attached to an adherend.

Further, since the above-mentioned water-soluble silicone-based surfactant does not impair the pH-selective water-soluble property of the base water-soluble pressure-sensitive adhesive, the water-soluble pressure-sensitive adhesive composition of the present invention is used in acidic water and neutral water. Can be used for adhesion in, and can be washed with alkaline water.

[0021]

EXAMPLES Hereinafter, the contents of the present invention will be clarified by giving examples and comparative examples of the present invention. Example 1 Acrylic acid: 20 parts by weight Butyl acrylate: 80 parts by weight The above composition and 100 parts by weight of ethyl acetate were charged in a batch in a separable flask at a temperature of 60 ° C. under a nitrogen atmosphere, and azobisisobutyrate. Copolymerization was carried out for 8 hours in the presence of 0.03 part by weight of ronitrile (hereinafter abbreviated as AIBN) to obtain an adhesive having a weight average molecular weight (Mw) of 600,000.

1 part by weight of SILWETFZ-2120 (trade name, manufactured by Nippon Unicar Co., Ltd.) as a surfactant was mixed with the above-mentioned pressure-sensitive adhesive, and the mixture was thoroughly stirred with a high-speed stirrer and then 1,6-
Hexamethylenediethylene urea (hereinafter abbreviated as HDU) was mixed in an amount of 0.5 part by weight, similarly thoroughly stirred and defoamed under reduced pressure to obtain an alkaline water-soluble pressure-sensitive adhesive composition of Example 1. Then, after degassing under reduced pressure, the surface of the polyethylene terephthalate film (hereinafter referred to as PET film) having a thickness of 38 μm is rapidly coated and dried to a thickness of 50 μm on the one surface thereof, and dried. Example 1
It was used as a test tape.

Example 2 Surfactant SILWET FZ-2120 was mixed in an amount of 3
Except for using 1 part by weight, an alkali water-soluble pressure-sensitive adhesive composition of Example 2 was obtained in the same manner as in Example 1, and this alkali water-soluble pressure-sensitive adhesive composition was used in the same manner as in Example 1. Test tape was prepared. Example 3 The surfactant used was manufactured by Nippon Unicar Co., Ltd., trade name: S
Except for changing to ILWET L-7002,
An alkaline water-soluble pressure-sensitive adhesive composition of Example 3 was obtained in exactly the same manner as in Example 1, and a test tape was prepared in the same manner as in Example 1 using this alkaline water-soluble pressure-sensitive adhesive composition.

Example 4 As a surfactant, 1,5-bis (methoxytriethylene glycol) was used instead of SILWET FZ-2120.
Alkaline water-soluble pressure-sensitive adhesive composition of Example 4 in the same manner as in Example 1 except that 0.5 part by weight of -1,1,3,3,5,5-hexamethyltrisiloxane was blended. Was obtained, and a test tape was prepared in the same manner as in Example 1 using the alkaline water-soluble pressure-sensitive adhesive composition.

[0025] Except for not blending the Comparative Example 1 surfactant SILWET FZ-2120, to give the adhesive composition of Comparative Example 1 in the same manner as in Example 1, using a PSA composition A test tape was prepared in the same manner as in Example 1. Comparative Example 2 The pressure-sensitive adhesive composition of Comparative Example 2 was prepared in the same manner as in Example 1 except that 3 parts by weight of polyethylene glycol (molecular weight 8000) was used in place of the SILWET FZ-2120 blended in Example 1. Then, a test tape was prepared in the same manner as in Example 1 using the pressure-sensitive adhesive composition.

Comparative Example 3 SILWET FZ-212 compounded in Example 1
Instead of 0, dioctyl phosphate (hereinafter referred to as DOP
Abbreviated. ) Example 1 except that 3 parts by weight were blended
A pressure-sensitive adhesive composition of Comparative Example 3 was obtained in the same manner as above, and a test tape was prepared in the same manner as in Example 1 using the pressure-sensitive adhesive composition. Using the test tapes of Examples 1 to 4 and Comparative Examples 1 to 3 prepared as described above, the water solubility, the initial adhesive strength, the adhesion accelerating property, and the removability of each adhesive composition were measured as follows. It was measured.

Each water-soluble test tape was cut into a 10 mm square, and the cut test piece was pressure-bonded to an epoxy plate at a pressure of 2 kg / cm ₂ . next,
The test piece crimped to the epoxy plate is as it is, as shown in Table 1 below.
The sample was dipped in each of the acidic, neutral and alkaline aqueous solutions for 60 minutes, and the tape was peeled off when immersed in each aqueous solution, and the presence or absence of elution of the compound into each aqueous solution was measured. The results are shown in Tables 2 and 3.

[0028]

[Table 1]

[0029]

[Table 2]

[0030]

[Table 3]

As is clear from Table 2, the test tapes of Examples 1 to 4 and Comparative Example 1 were completely peeled off when immersed in an alkaline aqueous solution, but were completely peeled off in the neutral aqueous solution and the acidic aqueous solution. I couldn't do it. On the contrary,
In the test tape of Comparative Example 2, partial peeling was observed when immersed in neutral water and acidic aqueous solution, while Comparative Example 3
No peeling was observed with the test tape of 1) in neutral water and an acidic aqueous solution, but the peeling when immersed in an alkaline aqueous solution was only partial.

As is clear from Table 3, Example 1
4 and the test tapes of Comparative Example 1, the formulation was dissolved when immersed in the alkaline aqueous solution, and no elution of the formulation was observed in the neutral water and the acidic aqueous solution. In contrast,
In the test tape of Comparative Example 2, dissolution of the formulation was observed even when immersed in neutral water and acidic aqueous solution, and in the test tape of Comparative Example 3, the formulation was not eluted when immersed in any aqueous solution. Therefore, Examples 1 to 4 and Comparative Example 1
It can be seen that the alkaline water-soluble pressure-sensitive adhesive composition (1) can withstand neutral water and an acidic aqueous solution, and can be easily removed by washing with an alkaline aqueous solution.

Initial Adhesion Strength and Adhesion Advancement Property Using the test tapes prepared in Examples 1 to 4 and Comparative Examples 1 to 3, the initial adhesion force and adhesion advancement property were evaluated. In the evaluation, 180 was applied to a stainless plate (hereinafter abbreviated as SP) and a glass-epoxy plate (hereinafter abbreviated as EP).
° Peel adhesion was measured by measuring. That is, each test tape was slit into a width of 10 mm, and 120 ° C.
A test piece is prepared by pressing the SP or EP heated to 2 mm with a rubber roller of 2000 g at a speed of 300 mm / min to a SP or EP heated to a temperature of 23 ° C. and a relative humidity of 50% RH, and a pulling speed. Peel 180 ° at 300 mm / min,
The peel strength was measured. The initial adhesive strength is
The value measured after 60 minutes passed in the measurement environment was adopted. In addition, regarding the adhesion accelerating property, 60 ° C at 60 ° C after application.
The 180 ° peel adhesion measured after curing for minutes was evaluated by the rate of increase with respect to the initial adhesion. The results are shown in Table 4.
And shown in Table 5.

[0034]

[Table 4]

[0035]

[Table 5]

As is clear from Tables 4 and 5, the test tapes of Examples 1 to 4 have a sufficient adhesive strength in both initial adhesive strength and adhesive progress as compared with the test tape of Comparative Example 1. You can see that it is suppressed. In particular, in Comparative Example 1 in which the silicone-based surfactant was not blended, the adhesive force after promotion was increased by 50% or more, whereas in the test tapes of Examples 1 to 4, the silicone-based surfactant was blended. Therefore, it can be seen that the adhesive force increase rate is very small. Similarly, even when polyethylene glycol is used alone as in Comparative Example 2, the adhesive strength after the increase is still increased by about 50%, and thus it is understood that the effect of suppressing the increase phenomenon is small.

Further, in Comparative Example 3, Japanese Patent Laid-Open No. 52-623.
As disclosed in No. 47, DOP was blended in order to suppress the accelerating phenomenon, and bleeding out at the adhesive interface in the same manner as the silicone-based surfactant was carried out. It can be seen that the effect of suppressing the progress phenomenon is lower than in the cases of Examples 1 to 4. Not only that, in the test tape of Comparative Example 3, although the tackiness was suppressed by blending DOP, the solubility in the alkaline aqueous solution was low as shown in Table 2. As is clear from Tables 2 to 5, the test tapes using the alkaline water-soluble pressure-sensitive adhesive compositions of Examples 1 to 4 of the present invention have removability without impairing the solubility in an alkaline aqueous solution. It can be seen that the improvement of the adhesiveness and the suppression of the adhesion promotion phenomenon are achieved.

[0038]

As described above, according to the present invention, an alkaline water-soluble adhesive which is insoluble in acidic water and neutral water but soluble only in alkaline water has the above specific water dispersibility or water solubility. Since the hydrophobic silicone-based surfactant is blended in the above-mentioned specific ratio, not only the pH-selective water-solubility is excellent, but also the adhesion promotion phenomenon that the adhesive force increases with time is effectively suppressed. Therefore, when the alkaline water-soluble pressure-sensitive adhesive composition of the present invention is used for a pressure-sensitive adhesive tape or sheet, it can be easily adhered to the adherend under a high-temperature and high-humidity condition for a long time without causing an adhesive residue phenomenon. Can be peeled again.

Moreover, even if the specific water-dispersible or water-soluble silicone surfactant is blended, the pH-selective water-solubility of the alkaline water-soluble pressure-sensitive adhesive is not impaired. Therefore, the alkaline water-soluble pressure-sensitive adhesive does not dissolve in acidic water and neutral water, and therefore can adhere to the adherend in acidic water and neutral water. For example, when mechanically polishing a semiconductor chip with neutral water, fixing the semiconductor chip with the alkaline water-soluble pressure-sensitive adhesive composition of the present invention prolongs problems such as swelling and peeling due to polishing water. There is no. Moreover, since the alkaline water-soluble pressure-sensitive adhesive composition can be peeled off without leaving the pressure-sensitive adhesive on the semiconductor chip, it can be repeatedly used. Furthermore, since it can be easily dissolved and washed with alkaline water after use, it becomes possible to achieve deorganization as a solvent in all steps. Therefore, when the alkaline water-soluble pressure-sensitive adhesive composition of the present invention is used, it is not necessary to use an organic solvent such as CFCs from sticking to re-peeling, and a residue cleaning step, and thus defluorocarbon cleaning in the field of electronic materials can be performed. It becomes possible to promote.

Claims (1)

[Claims] 1. A water-dispersible or water-soluble silicone-based interface having a polyalkylene oxide chain in the molecule with respect to 100 parts by weight of an alkaline water-soluble adhesive which is soluble only in alkaline water and insoluble in acidic water and neutral water. An alkaline water-soluble pressure-sensitive adhesive composition comprising an activator in an amount of 10 parts by weight or less.