JPS5821941B2 - Rewetting adhesive for bonding substrates for interior decoration - Google Patents

Description

[Detailed description of the invention] The present invention relates to a rewetting adhesive for bonding substrates for interior decoration.

When bonding a flexible substrate such as paper, cloth, or plastic film to an adherend, rewetting adhesives are used once applied to the substrate to form an adhesive surface, and then used for use on the substrate. It is an adhesive that exhibits the desired adhesive properties by sometimes wetting the adhesive surface with water.

This product is widely used in various fields, including rewetting adhesive tape, backing adhesive for interior decoration substrates such as wallpaper, wall cloth, and sliding door paper, and backing adhesive for stamps and stickers.

Rewetting adhesives must not be blocked by moisture or heat while the substrates coated with them are stored in rolled tape or sheet form, and must not age over time; It is required to have a long bonding time after wetting the adhesive surface with water (so-called open time), and to have high adhesive strength immediately after application (initial adhesive strength) and permanent adhesive strength.

Furthermore, in addition to the above requirements, the rewetting adhesive for adhering interior decoration substrates is required to have the following properties.

■ When the adhesive is applied to the base material and dried, there is little curling property (wrinkles occur on the base material during installation, which seriously impairs the aesthetic appearance and is a fatal drawback).

). 2. The base material to which the adhesive is applied must be flexible (if it is rigid, creases will easily occur in the base material itself, and workability during construction will be poor).

). 3. Must have water resistance (substrates coated with adhesive are often printed on the back side, that is, the opposite side to the adhesive side; if water resistance is poor, wrinkles will occur in the substrate during the printing process.

). Conventionally, natural gums such as glue, dextrin, and gum arabic, and water-soluble synthetic polymers such as polyvinyl alcohol, polyacrylamide, and acrylamide/vinyl acetate copolymers have been known as the above-mentioned rewetting adhesives. are used alone or in combination.

However, natural gum has the fatal disadvantage that it cannot avoid deterioration due to its own decay, and when used with glue,
When applied, it has the disadvantage of making the substrate rigid, resulting in poor workability during construction, and dextrin, gum arabic, and the like have the disadvantage of poor initial adhesive strength.

Adhesives based on water-soluble synthetic polymers also have drawbacks such as the base material to which they are applied become too rigid, curling becomes noticeable, and initial adhesion strength is insufficient.
Furthermore, there are some that cause wrinkles on the base material during the printing process.

As described above, all of the conventional adhesives have some drawbacks, and are still unsatisfactory as rewetting adhesives for adhering interior decoration substrates.

In view of the current situation, the present inventors conducted extensive research and found that certain types of acrylamide-acrylic acid ester copolymers or acrylamide-acrylic acid ester-vinyl acetate copolymers are suitable for interior decoration substrates. The present invention was completed based on the discovery that this adhesive exhibits extremely excellent performance as a rewetting adhesive for use in other applications.

That is, the present invention provides acrylamide (hereinafter referred to as component a) 3
0 to 90% by weight and 10 to 70% by weight of b acrylic ester (hereinafter referred to as component) or 30 to 90% by weight of component a
A water-based copolymer (hereinafter sometimes simply referred to as "copolymer") obtained by emulsion polymerization, comprising 3% by weight or more of component B and 67% by weight or less of C vinyl acetate (hereinafter referred to as component C) as constituent monomers.

) is a rewetting adhesive for adhering interior decoration substrates.

The rewetting adhesive of the present invention has the specific copolymer as the main component that maintains a good balance between water wettability and water resistance, exhibits excellent initial adhesive strength, and has a long open time.
Furthermore, wrinkles do not occur during the printing process.

Further, the above-mentioned copolymer has a suitable degree of flexibility, and the substrate coated with the copolymer exhibits almost no curling property, so that the construction work is easy and the finish after construction is beautiful.

Furthermore, the above-mentioned copolymer has excellent aging resistance, and when the coated substrate is stored for a long period of time, there is almost no decrease in the initial adhesive strength or the adhesive strength after application.

These excellent properties are due to the above-mentioned component a or component a.
Only certain copolymers formed by copolymerizing a predetermined amount of component C and component C are permitted.

Copolymers of homopolymers and monomers of component a, component b, or component C with monomers other than secondary monomers, and even copolymers of component a and component C, the proportion of secondary constituent monomers is the same. If it is outside the scope of the invention, the above characteristics will not be exhibited.

That is, the copolymer of the present invention has a component a of 30 to 9 as described above.
0% by weight, preferably 50-80% by weight and io of component b
-70% by weight, preferably 20-50% by weight of the constituent monomers, or 30-90% by weight of component a, preferably 5% by weight.
0 to 80% by weight, 3% by weight or more of component b, preferably 5 to 80% by weight
35% by weight and 67% by weight or less of component C, preferably 15% by weight
It is essential that the constituent monomer accounts for ~45% by weight.

If component a is less than 30% by weight, water wettability will be insufficient and the initial adhesive strength will be low, while if it exceeds 90% by weight, the water resistance will be poor and the coated substrate will have significant curling properties, both of which will not meet the desired results. This makes it unsuitable as a rewetting adhesive.

Furthermore, if the above-mentioned components are less than 3% by weight, water resistance and aging resistance will be poor, and the flexibility will be poor, so the base material will easily crease and the texture of the base material after lamination will be impaired. It cannot have the characteristics of a rewetting adhesive.

The acrylic ester used as component b in the present invention is preferably an ester of acrylic acid and a monohydric alcohol having 1 to 12 carbon atoms, specifically methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate. , hexyl acrylate, 2-ethylhexyl acrylate, and dodecyl acrylate.

Among these, esters with monohydric alcohols having 2 to 8 carbon atoms can be preferably used.

In addition, in the case of using component C in the present invention, the production cost can be reduced without reducing the performance of the product as an adhesive at all in comparison with the component a-component binary copolymer of the present invention. It is advantageous to have the advantage of reducing

The above-mentioned component a-component or component a-component-C component copolymer used as the main components of the adhesive in the present invention can be produced by copolymerizing each monomer according to various known methods, and the method is particularly Although not limited, it is preferable to use the following method, for example.

That is, benzoyl peroxide, cumene hydroperoxide, ammonium persulfate, etc., at a temperature of 10 to 90°C in a hydrophilic organic solvent such as methanol, ethanol, impropatol, acetone, ethyl acetate, water or a mixed solvent thereof. The above monomers are copolymerized using a peroxide such as , potassium persulfate, azobisisobutyronitrile, or an organic azo compound as a polymerization initiator.

In this case, surfactants and protective colloids are used.

Any known surfactant can be used, but nonionic surfactants are preferred, such as polyoxyethylene alkyl ether, polyoxyethylene aryl ether, polyoxyethylene polyoxypropylene block polymer, polyethylene Suitable examples include glycol fatty acid ester and sorbitan fatty acid ester.

The adhesive of the present invention is usually used in the form of a solution, etc., by dissolving or dispersing the copolymer in a suitable solvent.

Although the concentration of the copolymer is not particularly limited, it is usually about 5 to 30% by weight, and the solvent used is generally water or a mixed solvent of water and the above-mentioned hydrophilic organic solvent.

If necessary, pigments, fillers, preservatives, antifungal agents, antifoaming agents, etc. can be added to this adhesive liquid according to conventional methods.

Furthermore, glue, dextrin, polyvinyl alcohol, polyacrylamide, polyethylene glycol, carboxymethyl cellulose, etc. can also be used in combination within a range that does not impede the properties of the above copolymer.

When actually using the adhesive of the present invention, the adhesive of the present invention is applied to a flexible substrate such as paper, cloth, plastic film, etc. using a blade coater, a roll coater, etc. in accordance with a method commonly used for known rewetting adhesives. The method used is to apply the adhesive using a coater, air knife coater, etc. and then dry it to form an adhesive surface.

At this time, the amount of adhesive applied is usually 5 to 30 g/d (in terms of solid content).

Then, by printing or textile-printing a number design or pattern on the back side of the base material according to a conventional method, interior decoration products such as wallpaper, wall cloth, and fusuma paper can be obtained.

Examples and comparative examples will be shown below to clarify the features of the present invention.

In the examples, "part" and "1%" are based on weight.

Example 1 1/3 of the following composition was placed in a four-eye flask equipped with a stirrer, thermometer, nitrogen gas inlet, and dropping funnel, heated to 70°C while passing nitrogen gas, and then heated at the same temperature. Stir for 30 minutes.

Then, the remaining composition was added dropwise over a period of 3 hours, and after the addition was completed, the temperature was raised to 85° C. and maintained for 1 hour to complete the polymerization reaction.

After cooling, use a 20% aqueous solution of caustic soda to remove p after the reaction.
The H value is adjusted to 6 to 7 to obtain rewetting adhesives A-C of the present invention.

Acrylamide 65 parts Acrylic ester 35 Potassium peroxide 0.5 Emulsifier (nonionic) Q, 4tt Isopropyl alcohol 5 Deionized water 395 ・〃 Table 1 shows the type of acrylic ester used and the properties of the adhesive. show.

In the column of acrylic esters in Table 1, EA stands for ethyl acrylate, BA stands for butyl acrylate, and EH
A represents 2-ethylhexyl acrylate, and the same applies hereinafter.

Example 2 The procedure of Example 1 was repeated except that 75 parts of acrylamide and 25 parts of ethyl acrylate (Adhesive D) or 55 parts of acrylamide and 45 parts of ethyl acrylate (Adhesive E) were used. An inventive rewet adhesive adhesive and E is obtained.

Each has the properties listed in Table 2 below.

Example 3 Composition a having the following composition was placed in a flask similar to Example 1, heated to 70° C. while passing nitrogen gas, and at the same temperature, the following composition A was added dropwise over a period of 4 hours.

After completion of the dropwise addition, the temperature was raised to 85°C and kept at this temperature for 1 hour to complete the polymerization reaction.

After cooling, the pH is adjusted with a 20% aqueous solution of caustic soda to obtain the rewetting adhesive F-H of the present invention.

Composition a Table 3 shows the type of acrylic ester used and the properties of the adhesive.

Example 4 Adhesives ■ and J of the present invention were prepared in the same manner as in Example 3 except that acrylamide (AM), butyl acrylate (BA) and vinyl acetate (VAc) were used in the proportions shown in Table 4 below. get.

The properties of the obtained adhesive are shown in Table 4 below.

For comparison, Table 4 also shows similar properties for comparative adhesives K and L, which were obtained in the same manner without using BA.

Adhesives A-J obtained in the present invention and comparative adhesives for comparison included L, polyacrylamide (PAM) aqueous solution (concentration 2
0%, viscosity (25℃) 2000 cps) and polyvinyl alcohol (PVA) aqueous solution (concentration 20%, viscosity (2000 cps))
The following tests were conducted using 25° C.) 600 cps) as a rewetting adhesive for fusuma paper.

1) Initial adhesion test Commercially available fusuma paper (with gauze on the front, basis weight 8og7',
(It is.

) with each of the above adhesives on the back side, the solid weight of which is 109 /
Coat it so that it becomes yj, and apply a tension of 597cm to 10
It was left standing for 10 minutes in a circulating air dryer adjusted to 0°C.

The above coated paper was conditioned for 24 hours at 20° C. and 65% RH, and then cut into tanzag shapes 2 cm wide and 10 degrees long to be used as test paper material.

Wet the adhesive side of this paper stock with a wetter for duct tape to wet it (30 g/m"). After 30 seconds, press it by hand to a liner (basis weight 2809/m"), and after 10 minutes, wet it to 900 g/m".
Adhesive strength was measured by peeling method.

The test was conducted 10 times for each adhesive, and the average value was used for evaluation.

The results are shown in Table 5. 2) Accelerated Aging Test The test paper stock in 1) above was allowed to stand for 72 hours in a circulating dryer adjusted to 75°C, and then conditioned at 20°C and 65% humidity for 24 hours.

Then, the adhesive strength after aging was measured in the same manner as in 1) above.

The test was conducted 10 times for each adhesive, and the average value was used for evaluation.

The results are shown in Table 5. Note that the above aging conditions correspond to aging for 6 months or more at room temperature.

3) Blocking test Similarly to 1) above, a tanzak-shaped paper stock with a width of 2 (1771 cm and a length of 5 cfrL) was prepared, the gauze side and the glue side were overlapped, and a load of 500 g was applied thereto. ,75%R
, H atmosphere.

The state of blocking was observed for 24 hours.

The results are shown in Table 5.

4) Curling test Apply the adhesive in 1) above, release the tension after drying, and
Table 6 shows the three results of observing the presence or absence of curl in the stock after 0 minutes.

5) Water resistance test Pour the adhesive onto a polyethylene plate and heat it at 20°C, 65% R,
It was left standing in an atmosphere of H for 2 weeks to create a film with a thickness of 0.5 m.

Cut this film into 5 cIrL lengthwise and 4cIrL width.
The film was poured into 100 ml of water (25°C), stirred vigorously, and the time required for the film to completely dissolve was measured.

Table 6 shows the results of repeating the test four times and using the average value for each adhesive.

6) Flexibility test The film obtained in 5) above was dried at 100°C for 3 hours and then cut into tanzak shapes with a width of 1 cIrL and a length of 5 crrL.
The film was stored in a desiccator at 20° C. for 24 hours, and the elongation (%) of the film was measured at a tensile rate of 10 CIrL/min and a span of 1 CIrL.

The test was repeated four times for each adhesive and the average values are shown in Table 6.

In addition, each of the adhesives AA=J of the present invention was coated on commercially available wallpaper (basis weight 15 og/m) so that the solid content weight was 209/rrl, dried at 120°C for 5 minutes, and then printed. However, no wrinkles were observed in any of the adhesives.

In addition, each of these wallpapers was cut into 1-meter-wide pieces and applied to the walls, but they were flexible and did not crease during work, nor did they curl after getting wet, resulting in a beautiful finish.

Claims (1)

[Claims] 1 a 30 to 90% by weight of acrylamide and b 10 to 70% by weight of acrylic ester or a 30% by weight of acrylamide
- 90% by weight, B: 3% or more by weight of acrylic acid ester, C: 67% by weight or less of vinyl acetate as constituent monomers, and a base material for interior decoration characterized by having as a main component an aqueous copolymer obtained by emulsion polymerization. Rewet adhesive for bonding. 2 C component containing 30 to 90% by weight of water-based copolymer and 10
Adhesive 33 according to claim 1, wherein the constituent monomer is ~70% by weight of component B. The aqueous copolymer comprises 50 to 80% by weight of component C and 20 to 50% by weight of component b.
The adhesive according to claim 2, wherein the component is a constituent monomer. 4. The adhesive according to claim 1, wherein the aqueous copolymer has 30 to 90% by weight of the C component, 3% by weight or more of the b component, and 67% by weight or less of the C component as constituent monomers. 5 C component containing 50 to 80% by weight of water-based copolymer, 5 to 3
The adhesive according to claim 4, wherein the constituent monomers are 5% by weight of component B and 15 to 45% by weight of component C. 6. Claims 1 to 5, wherein component b is an ester of acrylic acid and a monohydric alcohol having 1 to 12 carbon atoms.
Adhesives described in any of paragraphs. 7. The adhesive according to claim 6, wherein the monohydric alcohol has 2 to 8 carbon atoms.