JPH111597A - Aqueous emulsion composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition excellent in flame retardance, mechanical strengths, embossing characteristics, etc., without using vinyl chloride by including a specific resin component, thermally expandable hollow microspheres and an inorganic filler in a specific proportion therein. SOLUTION: This aqueous emulsion composition is obtained by including (A) 100 pts.wt. resin component, having a core/shell structure and comprising the core part composed of (i) a copolymer, comprising 90-99.9 wt.% (meth)acrylic ester and 10-0.1 wt.% functional monomer having one ethylenically unsaturated double bond and a functional group reactive with hydroxyl groups and carboxyl groups when heated and having -50 to -10 deg.C glass transition temperature and the shell part composed of (ii) a copolymer, comprising 90-99 wt.% (meth) acrylic ester and 10-1 wt.% α,β-ethylenically unsaturated carboxylic acid and having 40-80 deg.C glass transition temperature at (50/50) to (90/10) weight ratio of the components (i)/(ii), (B) 5-50 pts.wt. thermally expandable hollow microspheres as a foaming agent and (C) 50-350 pts.wt. inorganic filler.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an aqueous emulsion composition and a foamed sheet. More specifically, the present invention is excellent in flame retardancy, and is excellent in mechanical strength, folding resistance, water resistance, blocking resistance, foaming properties and embossing properties required as essential requirements for foamed wallpaper, and therefore, for wallpaper and the like. The present invention relates to an aqueous emulsion composition and a foamed sheet that are optimally used for the above-mentioned applications.

[0002]

2. Description of the Related Art Conventionally, aqueous emulsion compositions for flame-retardant foamed sheets have been used for wallpaper applications. Conventional emulsions use a copolymer containing vinyl chloride as a polymer component and maintain their flame retardancy. However, wallpaper using a copolymer containing vinyl chloride generates harmful chlorine gas during incineration, and has disadvantages in terms of the global environment and working environment. As a method of solving such a problem, Japanese Patent Application Laid-Open No. 7-108640 discloses an invention relating to an acrylic resin-based decorative sheet material. However, this method was unsatisfactory in obtaining sufficient foamability and folding resistance.

[0003]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the problem to be solved by the present invention is to use vinyl chloride which is not preferable in view of the above points, to provide excellent flame retardancy, and to provide essential elements for foamed wallpaper. The present invention is to provide an aqueous emulsion composition and a foamed sheet which are excellent in mechanical strength, folding resistance, water resistance, blocking resistance, foaming property and embossing properties, which are required as follows.

[0004]

That is, one aspect of the present invention is the following [A] 100 parts by weight, [B] 5 to 50 parts by weight.
Pertaining to an aqueous emulsion composition containing 100 parts by weight and 50 to 350 parts by weight of [C]. [A]: It has a core / shell structure, the core part is composed of the following copolymer (Ac), and the shell part is the following copolymer (As)
And the weight ratio of (Ac) / (As) is 50 / 50-
90/10 resin component (Ac): 90 to 99.9% by weight of (Ac1) and 10 to 0.1% by weight of (Ac2) having a glass transition temperature of −50 to −10 ° C. Combined (Ac1): (meth) acrylate (Ac2): Functional monomer having one ethylenic double bond and having a functional group that reacts with a hydroxyl group and a carboxyl group when heated (As): (As1) shown below ) 90-99% by weight and (As
2) 10 to 1% by weight, having a glass transition temperature of 40 to
80 ° C. copolymer (As1): (meth) acrylate (As2): α, β-ethylenically unsaturated carboxylic acid [B]: heat-expandable hollow microspheres [C]: inorganic filler

Another aspect of the present invention relates to a foamed sheet or wallpaper obtained by using the above-mentioned aqueous emulsion composition.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION [A] of the present invention has a core / shell structure, in which the core is composed of a copolymer (Ac), the shell is composed of a copolymer (As), and (Ac) / (As)
Is a resin component having a weight ratio of 50/50 to 90/10.

The copolymer (Ac) is (Ac1) 90 to 9
The copolymer is composed of 9.9% by weight and (Ac2) 10 to 0.1% by weight, and has a glass transition temperature of -50 to -10C.

(Ac1) is a (meth) acrylate ester such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, heptyl acrylate,
Octyl acrylate, 2-ethylhexyl acrylate, decyl acrylate, lauryl acrylate, stearyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate, methacrylic acid- Examples thereof include 2-ethylhexyl, decyl methacrylate, lauryl methacrylate, and stearyl methacrylate. These may be used alone or in a combination of two or more.

(Ac2) is a functional monomer having one ethylenic double bond and having a functional group which reacts with a hydroxyl group and a carboxyl group upon heating.
N-methylol derivative monomers such as methylol acrylamide and N-butoxymethyl acrylamide; amino group-containing monomers such as dimethylaminoethyl methacrylate and dimethylaminopropyl acrylamide; epoxy group-containing monomers such as glycidyl (meth) acrylate; acrylamide, methacrylamide; Examples include amide group-containing monomers such as maleamide.

The (Ac) of the present invention may contain an α, β-ethylenically unsaturated carboxylic acid (Ac3). (Ac
Examples of 3) include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, maleic anhydride and the like.

The content of each component of the copolymer (Ac) is 90 to 99.9% by weight of (Ac1) and (Ac2) 1
0 to 0.1% by weight. When (Ac3) is contained, (Ac1) 80 to 99.9% by weight, (Ac2)
10 to 0.1% by weight and (Ac3) 10% by weight or less. If (Ac1) is too small, the foaming properties are inferior.
If c1) is excessive, folding resistance, mechanical strength, and water resistance are poor. If (Ac2) is too small, folding resistance, mechanical strength, and water resistance are poor. On the other hand, if (Ac2) is too large, foaming properties are poor. If the content of (Ac3) is excessive, the foaming properties and folding resistance are poor.

The glass transition temperature (T) of the copolymer (Ac)
g) is -50 to -10C, preferably -45 to-
20 ° C. If the glass transition temperature is too low, the blocking resistance is poor, while if the glass transition temperature is too high, the foaming properties and folding resistance are poor.

The copolymer (As) is (As1) 90 to 9
A copolymer comprising 9% by weight and 10 to 1% by weight of (As2) and having a glass transition temperature of 40 to 80 ° C.

(As1) is a (meth) acrylic ester, and specific examples thereof include those described in the above section (Ac1).

(As2) is an α, β-ethylenically unsaturated carboxylic acid, and specific examples thereof include those described in the above section (Ac3).

The content of each component of the copolymer (As) is (As1) 90 to 99% by weight and (As2) 10 to 10% by weight.
1% by weight. When (As1) is too small, the foamability is poor. On the other hand, when (As1) is excessive, the blocking resistance is poor. If (As2) is too small, the blocking resistance is poor, and the stability of the particles and the dispersibility of the filler are also poor. On the other hand, when the content of (As2) is excessive, the folding resistance and the foaming property are poor.

The glass transition temperature (T) of the copolymer (As)
g) is 40-80 ° C. If the glass transition temperature is too low, the blocking resistance will be poor, while if the glass transition temperature is too high, the folding resistance will be poor and the film forming properties of the coating film will deteriorate. The glass transition temperature in the present invention is determined by the Fox equation.

The weight ratio of / (As) in [A] is 50/5
0 to 90/10. When the content of (Ac) is too small, the foaming property and the folding resistance are poor. On the other hand, when the content (Ac) is too large, the blocking resistance is poor.

[A] of the present invention is a resin component having a core / shell structure. Here, the core / shell structure is a structure in which the core and outer shell of the particles are different from each other, and the composition of the polymer of the seed emulsion to be polymerized first and the composition of the polymer to be polymerized later are variously changed. By doing
An emulsion having a core / shell structure is obtained.

[B] of the present invention is a thermally expandable hollow microsphere. A heat-expandable hollow microsphere expands when heated.
A foaming agent composed of microspheres that can be foamed, for example, polyacrylonitrile, a copolymer of acrylonitrile and methyl acrylate, polyvinylidene chloride,
It is a sphere having a particle diameter of 1 to 50 μm containing a low-boiling hydrocarbon such as ethane, propane, butane, pentane, hexane or heptane inside a shell portion made of a copolymer of vinylidene chloride and acrylonitrile. As the component (B), a commercially available product (for example, trade name “Microsphere” manufactured by Matsumoto Yushi Co., Ltd.) can be used.

[C] of the present invention is an inorganic filler,
Specific examples thereof include aluminum hydroxide, magnesium hydroxide, barium hydroxide, calcium carbonate, magnesium carbonate, calcium sulfate, barium sulfate, and primary hydroxide.
Examples include iron, basic zinc carbonate, basic lead carbonate, silica sand, clay, talc, silicas, titanium dioxide, magnesium silicate, and the like. Preferred are aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, ferrous hydroxide, basic zinc carbonate, and titanium dioxide.

The aqueous emulsion composition of the present invention comprises:
[A] 100 parts by weight, [B] 5 to 50 parts by weight and [C]
50 to 350 parts by weight, preferably [A] 100
Parts by weight, [B] 5 to 30 parts by weight, and [C] 60 to 250 parts by weight
Contains parts by weight. When [B] is too small, the foaming property is inferior. On the other hand, when [B] is too much, the mechanical strength is inferior and it is uneconomical. When [C] is too small, the flame retardancy is poor, while when [C] is too large, the foaming properties, mechanical strength and folding resistance are poor.

The aqueous emulsion composition of the present invention contains the following [D] in addition to the above [A] to [C], and the content of [B] is 100% by weight of the total of [A] and [D]. 5 to 50 parts by weight per part, the content of [C] is 50 to 350 parts by weight per 100 parts by weight of the total of [A] and [D], and the content of [D] is 100 [A]. 5 per part by weight
It may be about 100 parts by weight. By using [D], the expansion ratio can be further increased.

[D] is the following (D1): 5 to 35% by weight;
(D2) 95 to 35% by weight and (D3) 0 to 30% by weight
And a glass transition temperature of -25 to + 15 ° C. (D1): ethylene (D2): vinyl ester (D3): (meth) acrylate

(D1) The content of ethylene is usually 5 to 3
It is 5% by weight, preferably 10 to 30% by weight. If the content is too small, the composition is hard and has poor folding resistance and foaming properties. On the other hand, if the content is too large, the composition has poor mechanical strength and blocking resistance.

(D2) Examples of the vinyl ester include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl pivalate, vinyl laurate, vinyl versatate and the like. Preferably, vinyl acetate or a combination of vinyl acetate and another vinyl ester is used. The content of (D2) is usually from 95 to 35% by weight. When the content is too small, the mechanical strength and the blocking resistance are poor, while when the content is too large, the folding resistance and the foaming property are poor.

Specific examples of (D3) (meth) acrylic acid ester include those described in the above section (Ac1). The content of (D3) is 30% by weight or less. By using (D3) in this range, folding resistance, water resistance and durability can be improved.

When [D] is used, the content of [B] is 100 parts by weight to 50 parts by weight in total of [A] and [D], and the content of [C] is [A] and [D]. D] 1
00 parts by weight, 50 to 350 parts by weight, and [D]
Is from 5 to 100 parts by weight per 100 parts by weight of [A]. If [D] is too small, the effect of increasing the expansion ratio may be insufficient, while if [D] is too large, the blocking resistance may be poor.

The following method can be used as a method for obtaining the aqueous emulsion composition of the present invention. That is, water and a surfactant are charged into a polymerization vessel, and 50 ° C. to 8
Heat and raise the temperature to about 0 ° C. Next, the polymerization initiator and monomers (Ac1) and (Ac2), and if necessary, (A
c3) is polymerized for 3 to 4 hours. After the addition,
After aging for about 30 minutes, the monomers (As1), (As
2) is added over about 30 minutes, and after completion of the addition, a polymerization initiator is added over about 1 hour to carry out polymerization, followed by cooling to obtain an intended product.

Examples of the polymerization initiator include hydrogen peroxide, potassium persulfate, sodium persulfate, ammonium persulfate, t
tert-butyl hydroperoxide alone or L-, D-ascorbic acid, sulfite, Rongalit,
A redox system combined with a reducing agent such as ferrous sulfate can be used. During the polymerization, a pH adjuster such as an alkali metal hydroxide, aqueous ammonia, a base such as an amine, an acid such as hydrochloric acid, phosphoric acid, acetic acid, succinic acid, or carbonic acid and a salt thereof may be used. And the like.

The aqueous emulsion composition of the present invention has the above-mentioned excellent characteristics, and is optimally used for producing a foamed sheet, particularly for producing a wallpaper, taking advantage of the characteristics. In order to use the aqueous emulsion composition of the present invention as a foam sheet such as wallpaper, for example, the composition is coated with a roll coater, reverse roll coater, doctor coater, etc., screen printing, gravure printing, engraving roll printing, flexographic printing. It may be applied to or printed on paper using a concavo-convex printing method such as described above, dried, and then subjected to foaming treatment and embossing.

[0032]

Next, the present invention will be described with reference to examples.

Example 1 [Preparation of Aqueous Emulsion Composition] Into a 5 L SUS reactor equipped with a reaction temperature controller and a stirrer, 8 g of Emar 2F needle, sodium lauryl sulfate (manufactured by Kao Corporation), was added.
And 4 g of Emulgen 931 (manufactured by Kao Corporation), which is a polyoxyethylene nonylphenyl ether, and 1500 g of water. After the temperature was raised to 75 ° C., 182 g of methyl methacrylate (Ac1) and 1000 g of butyl acrylate (A
12 g of glycidyl methacrylate as c2), (Ac
As 3), 6 g of acrylic acid was added to the reaction system over a period of 3 hours at a constant rate.
It was added to the reaction system over 4 hours at a constant rate of 0 g to obtain an emulsion having a core structure. Furthermore, at 75 ° C, 30
After aging (leaving), 320 g of methyl methacrylate, 70 g of butyl acrylate, (As)
As 2), 10 g of acrylic acid was added to the reaction system over 30 minutes. Then, 40 g of a 4% aqueous potassium persulfate solution was added to 1
The mixture was added to the reaction system over a period of time, and after completion of the addition, the mixture was heated to 80 ° C. and aged for 1 hour to give an aqueous emulsion (solid content = 49%)
I got

[ Distribution of emulsion for flame-retardant foam sheet ]
Combination] In 204 parts of the emulsion (100 parts of solid content) obtained as described above, 15 parts of water, 20 parts of Microsphere F-85D (manufactured by Matsumoto Yushi Co., Ltd.) as [B], and aluminum hydroxide C as [C] -303 (manufactured by Sumitomo Chemical Co., Ltd.) and 120 parts of titanium dioxide R-820 (manufactured by Ishihara Sangyo)
0 parts were mixed and dispersed by a homomixer. A small amount of a thickener (Toa Gosei Chemical Industry Alon A-20) is added to the obtained mixture.
L) was added to adjust the viscosity to 6000 mPa · s (BL viscometer 12 rotations) to obtain an emulsion composition for a flame-retardant foamed sheet (solid content = 66%). The composition is applied to a wallpaper base paper so that the thickness after drying is 0.15 mm,
The foam was dried by drying at 120 ° C. for 5 minutes and further heated at 180 ° C. for 1 minute. The obtained foam was evaluated as follows. In addition, (7) coating suitability is an evaluation before foaming.

(1) Foamability The foaming ratio (= thickness of foam / thickness of dry coating film) was evaluated. (2) Water resistance The foam was immersed in water at 20 ° C. for 24 hours, and the appearance was observed.
（(Good: no swelling and dissolution), △ (partially swelling) and × (partially dissolving) were evaluated. (3) Blocking resistance The coating surfaces of the two foams are overlapped and put together at 45 ° C., 9
Under a condition of 0% RH (relative humidity), a load of 5 kg / cm ² was left for 24 hours. Thereafter, the foams were peeled off from each other and evaluated according to the criteria of ○ (no resistance), Δ (with resistance), and × (breakage of material). (4) Folding resistance The foam was bent at 180 degrees, the appearance of the bent portion was observed, and the evaluation was based on the criteria of ○ (no abnormality), Δ (partially cracked), and × (cracked on the entire surface). (5) Mechanical strength The appearance of the foam was rubbed with a finger to observe the appearance, and the appearance was evaluated as follows: ○ (no abnormality), Δ (partially scratched), and × (surface peeling of the coating film)
Was evaluated based on the following criteria. (6) Flame retardancy (burning speed) A foam having a length of 300 mm and a width of 30 mm is suspended vertically,
Burning was performed for 5 seconds from the bottom with a burner, and the burning distance (burning speed) per minute was measured.

Examples 2 to 6 and Comparative Examples 1 to 6 The same procedures as in Example 1 were carried out except that the conditions shown in Tables 1 to 6 were used. The conditions and results are shown in Tables 1 to 6. The following can be seen from the results. In all examples satisfying the conditions of the present invention, satisfactory results are shown in all evaluation items. On the other hand, Comparative Example 1 where the glass transition temperature of (Ac) is too high, Comparative Example 2 where the glass transition temperature of (As) is too low, Comparative Example 3 where the (Ac) / (As) ratio is too small,
Comparative Example 4, in which the glass transition temperature of (Ac) is too low, (Ac)
Comparative Example 5 using a copolymer other than the present invention as 2) and Comparative Example 6 lacking the (Ac2) component showed unsatisfactory evaluation results as shown in Tables 4 and 6, respectively.

[0037]

[Table 1]

[0038]

[Table 2]

[0039]

[Table 3]

[0040]

[Table 4]

[0041]

[Table 5]

[0042]

[Table 6]

MMA: methyl methacrylate BA: n-butyl acrylate 2EHA: 2-ethylhexyl acrylate AA: acrylic acid MAA: methacrylic acid GMA: glycidyl methacrylate N-MAM: N-methylol acrylamide * 1 SLS: anion -Based surfactant (sodium lauryl sulfate) (values are parts by weight per 100 parts by weight of total monomers) * 2 PNE: Nonionic surfactant (polyoxyethylene nonylphenyl ether) (values are total weight of all monomers) * 3 B: Microsphere F-85D (Matsumoto Yushi Co., Ltd.) * 4 C C-303: Aluminum hydroxide C-303 (Sumitomo Chemical Co., Ltd.) R-820: Titanium dioxide R-820 (manufactured by Ishihara Sangyo) * 5 D: ethylene / Vinyl acetate / 2EHA = 24/7
0/6 (weight ratio) copolymer, Tg = -13 ° C * 6 EGDMA (ethylene glycol dimethacrylate) was used.

[0044]

As described above, according to the present invention, harmful chlorine gas is generated at the time of incineration, without using vinyl chloride which is not preferable from the viewpoint of global environment and working environment, excellent flame retardancy, and foaming. An aqueous emulsion composition and a foamed sheet having excellent mechanical strength, folding resistance, water resistance, blocking resistance, foaming properties and embossing properties required as essential requirements for wallpaper could be provided.

Claims (6)

[Claims] [1] 100 parts by weight of the following [A], [B] 5 to 5
An aqueous emulsion composition containing 0 parts by weight and 50 to 350 parts by weight of [C]. [A]: It has a core / shell structure, the core part is composed of the following copolymer (Ac), and the shell part is the following copolymer (As)
And the weight ratio of (Ac) / (As) is 50 / 50-
90/10 resin component (Ac): 90 to 99.9% by weight of (Ac1) and 10 to 0.1% by weight of (Ac2) having a glass transition temperature of −50 to −10 ° C. Combined (Ac1): (meth) acrylate (Ac2): Functional monomer having one ethylenic double bond and having a functional group that reacts with a hydroxyl group and a carboxyl group when heated (As): (As1) shown below ) 90-99% by weight and (As
2) 10 to 1% by weight, having a glass transition temperature of 40 to
80 ° C. copolymer (As1): (meth) acrylate (As2): α, β-ethylenically unsaturated carboxylic acid [B]: heat-expandable hollow microspheres [C]: inorganic filler 2. The composition according to claim 1, further comprising the following [D] in addition to [A] to [C], wherein the content of [B] is [A] and [D].
5 to 50 parts by weight per 100 parts by weight of the total amount of
The content of [C] is 50 to 350 parts by weight per 100 parts by weight of the total amount of [A] and [D], and the content of [D] is 5 to 100 parts by weight per 100 parts by weight of [A]. Aqueous emulsion composition. [D]: The following (D1) 5 to 35% by weight, (D2) 95 to
Copolymer consisting of 35% by weight and (D3) 0 to 30% by weight and having a glass transition temperature of −25 to + 15 ° C. (D1): ethylene (D2): vinyl ester (D3): (meth) acrylate 3. The aqueous emulsion composition according to claim 1, which is used for producing a foamed sheet. 4. The aqueous emulsion composition according to claim 3, wherein the foam sheet is wallpaper. 5. A foam sheet obtained by using the aqueous emulsion composition according to claim 3. 6. Wallpaper obtained by using the aqueous emulsion composition according to claim 4.