JPH01261480A - Amino resin adhesive composition - Google Patents

Abstract

PURPOSE:To reduce the formaldehyde odor and to prevent the discoloration and the generation of an odor when a rock wool board is manufactured, by mixing an amino resin adhesive with an acrylic emulsion at a specified ratio. CONSTITUTION:2.0-30.0 pts.wt., on a solid basis, of at least one acrylic emulsion having a solid content of a preferably 40-60wt.% is slowly added to 100 pts.wt., on a solid basis, of at least one amino resin adhesive having a solid content of preferably 40-70wt.% and comprising a melamine and/or urea-formaldehyde resin adhesive, and the pH of the mixture is adjusted to a prescribed value.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to the production of rock wool boards, rock wool sound absorbing boards and rock wool decorative sound absorbing boards obtained by secondary processing (surface processing) of the same. The present invention relates to suitable adhesive compositions.

Rock wool boards first appeared on the market around 1963, and since then they have gradually become popular as ceiling boards for buildings. This rock wool board has properties such as flame retardancy, non-combustibility, heat insulation, and sound absorption, so it can be used for secondary processing (surface treatment) to produce rock wool sound absorption boards and rock wool decorative sound absorption boards. Boards were developed, and from around 1975 they were widely used as ceiling panels in general homes, and are now used in office buildings, hotels,
It has come to be widely used as ceiling panels in hospitals, general homes, stores, etc.

[Prior art and problems to be solved by the invention] Rock wool boards are generally manufactured by the following method.

In other words, rock wool board is made by dispersing rock wool specified in JISA 9504 in water, making it into a board shape using the same method as paper making to a certain thickness, and making it into a board shape.
The molded wet-like rock wool plate is uniformly impregnated with the liquid adhesive to the inside by spraying or other methods. After that, 1 piece of this wet-shaped rock wool board
The rock wool board is cured by heating at a temperature of 00° C. or higher for several hours, and then the side surface is processed by rough cutting and finishing, or a combination of rough cutting and finishing to produce a product.

In the above manufacturing method, various starch aqueous solutions were initially used as the liquid adhesive, but later on, in order to make rock wool temporary lighter in weight, and also to make it nonflammable, water resistant, and strong, Amino resin adhesives have come into use.

However, when amino resin adhesives are used to manufacture rock wool boards, the rock wool boards may turn yellow during heating and curing, and the manufactured rock wool boards may become extremely unpleasant. There was an extremely inconvenient problem in that a fishy odor was generated.

Furthermore, since amino resin adhesives usually contain 2 to 3% free formaldehyde, in the process of heating and curing the rock wool board, this free formaldehyde is released into the atmosphere, which can pollute the working environment. The problem is that it gets worse.

Furthermore, since some of the formaldehyde in i3 remains in the rock wool board after heating and curing, there is a problem in that the rock wool board still emits a slight formaldehyde odor even after it is manufactured into a product.

Various methods have been proposed to solve these problems. For example, as a method to prevent the release of t1M formaldehyde, urea, ethylene urea, ammonium carbonate, dicyandiamide, sodium sulfite, etc. are added to the amino resin adhesive in advance. A method of adding a small amount is known. However, when an amino resin adhesive containing these compounds is used, a problem arises in that the physical properties such as the strength (flexural strength) and water resistance of the manufactured rock wool board deteriorate. Furthermore, among the above compounds, when urea, ethylene urea, and dicyandiamide are added, free formaldehyde is considerably reduced, but a new problem arises in that the fish odor becomes even more intense.

It is known that the cause of fishy odor is the presence of trimethylamine, which is thought to be generated from ammonia and formaldehyde, and the presence of trace amounts of copper or sodium formate can cause the formation of trimethylamine. It is also known that it is promoted. This reaction is also accelerated by heating.

The production of a small amount of formic acid is unavoidable in the production of amino resin, and therefore, if rock wool boards were produced by conventional methods using amino resin adhesives, the generation of formaldehyde and fish odors could be prevented. It is impossible to do so.

Additionally, as a method of preventing yellowing during heating and curing of rock wool boards, it is known to add a small amount of borax to the amino resin adhesive, but although this method has some effects, it is not satisfactory. cannot be obtained.

[Means for Solving the Problems] In view of this situation, the present inventors have conducted extensive studies with the aim of preventing yellowing, formaldehyde odor, and fish odor during heating and curing of the rock wool board. As a result of stacking, by using a composition in which acrylic emulsion is added to an amino resin adhesive in a specific proportion, the above objectives are not only achieved, but also the mechanical strength such as the bending strength of the rock wool board is improved. The present invention has been completed based on the discovery that this can be done.

That is, in the present invention, an acrylic emulsion is added as a solid content to an amino resin adhesive based on 100 parts by weight of the solid content.
The present invention provides an amino resin adhesive composition characterized in that it contains 0 to 30.0 parts by weight.

[Detailed disclosure of the invention]

The amino resin adhesive used in the present invention is a melamine-formaldehyde resin adhesive, a phosphorus-formaldehyde resin adhesive, and a melamine-urea-formaldehyde copolymer resin adhesive, all of which are manufactured by known methods. Preferably used.

Among these resin adhesives, melamine-formaldehyde resin adhesives are obtained by reacting formaldehyde in a ratio of 1 to 6 moles with respect to 1 mole of melamine. Potassium oxide (KOI), sodium carbonate (Naz
COs), an alkaline compound (alkali catalyst) such as aqueous ammonia (NH40H), and, if necessary, an acid (acid catalyst) such as hydrochloric acid or acetic acid.

Further, the above reaction is usually carried out at a temperature of 60 to 100'C. Urea-formaldehyde resin adhesive is urea 1
Formaldehyde is in a ratio of 1 to 3 moles per mole,
As in the production of the melamine-formaldehyde resin adhesive described above, it can be obtained by adding an alkali catalyst and, if necessary, an acid catalyst and causing the reaction to occur. Incidentally, the reaction at this time is carried out at a temperature of 60 to 100°C. Also, melamine
The urea-formaldehyde co-condensation resin adhesive contains 0.01 to 0.16 mol of melamine per mol of formaldehyde and 0.01 to 0.16 mol of urea per mol of formaldehyde.
It is obtained by reacting melamine and urea at a ratio of 0.99 mol and at a ratio where the total number of moles of melamine and urea does not exceed 1 mol per mol of formaldehyde. The types of alkali catalysts and acid catalysts added during the reaction are the same as in the production of the melamine-formaldehyde resin adhesive and urea-formaldehyde resin adhesive described above. Moreover, the reaction temperature is carried out in the range of 60 to 100°C.

In the present invention, the amino resin adhesive thus obtained preferably has a solid content of 40 to 70% by weight.

On the other hand, the acrylic emulsion used in the present invention can also be obtained by a known emulsion polymerization method. That is, an acrylic monomer (described later) is transported into an appropriate amount of water to which a small amount of an emulsifier and a polymerization initiator have been added, and the acrylic monomer is subjected to emulsion polymerization.

The acrylic monomer used in the present invention is methyl (
(Meth)acrylic acid alkyl esters such as meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, stearyl (meth)acrylate, glycidyl (
(meth)acrylic acid glycidyl esters such as meth)acrylate, (meth)acrylic acid hydroxy esters such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, (meth)acrylic acid, crotonic acid unsaturated basic acids and their salts; unsaturated dibasic acids such as itaconic acid, fumaric acid, maleic acid; Amides of unsaturated carboxylic acids such as meth)acrylamide, polyvalent vinyl compounds such as ethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, and acrylonitrile, etc. are used, and one or more of these may be used. Note that the term (meth)acrylic mentioned above means acrylic and methacrylic.

Examples of emulsifiers used in the emulsion polymerization of the acrylic monomers include known compounds such as sodium dodecylbenzenesulfonate, sodium dodecylsulfate, polyoxyethylene nonylphenol ether, and polyoxyethylene-polypropylene block copolymer. As the agent, potassium persulfate, ammonium persulfate, azobisisobutylnitrile, benzoyl peroxide, etc. are used. In addition, if the acrylic monomer is mixed in advance with a small amount of a known and commonly used chain transfer agent such as an organic ole compound such as dodecyl mercaptan or lauryl mercaptan, or an organic halogen compound such as chloroform or carbon tetrachloride,
This is preferred because the molecular weight can be controlled.

As mentioned above, emulsion polymerization is carried out by dropping the acrylic monomer into a suitable amount of water to which a small amount of emulsifier and polymerization initiator have been added, but the temperature of the water at this time is usually 0 to 0.
The range is 30°C.

In the present invention, the solid content of the acrylic emulsion is preferably 40 to 60% by weight in terms of ease of emulsion polymerization. This solid content can be adjusted by adjusting the amount of water mentioned above during emulsion polymerization.

The amino resin adhesive composition of the present invention is obtained by uniformly mixing one or more amine resin adhesives obtained by the above method and one or more acrylic emulsions obtained by the above method in a specific ratio. However, the mixing ratio of the acrylic emulsion as a solid content is 2.0 to 30.0 parts by weight, preferably 5.0 to 20.0 parts by weight, per 100 parts by weight of the solid content of the amino resin adhesive. If the proportion of the acrylic emulsion is less than 2.0 parts by weight, the effect of reducing formaldehyde odor and the effect of preventing discoloration of rock wool boards and fish odor will be reduced, which is disadvantageous.On the contrary, if the proportion exceeds 30.0 parts by weight, This is inconvenient because the fluidity of the amino resin adhesive composition deteriorates, making handling and workability difficult when manufacturing rock wool boards using the composition.
This is a problem because the heat resistance of the resulting rock wool board decreases.

Next, the method for producing the amino resin adhesive composition will be described in more detail.

The amino resin adhesive composition of the present invention can be produced as follows. That is, one or more of the amino resin adhesives obtained as described above are put into a container equipped with a stirrer, and while this is being stirred, the amino resin adhesives also obtained as described above are added. Gradually add and mix one or more acrylic emulsions, and then adjust the pH to 7 to 1 with an acid or alkali such as hydrochloric acid or sodium hydroxide.
It can be easily obtained by adjusting the value to an arbitrary value within the range of 0 and then stirring for about 30 minutes.

In addition, when using two or more types of amino resin adhesives in the above, the ratio is arbitrary. In this case, two or more types of amino resin adhesives may be separately put into the container and stirred and mixed. Further, when two or more types of acrylic emulsions are used, the ratio is arbitrary, but in this case, the two or more types of acrylic emulsions are mixed well in advance and then gradually added to the container.

The above amino resin adhesive and acrylic emulsion are mixed and pH adjusted at room temperature.

In addition, when mixing the amino resin adhesive and the acrylic emulsion, it is necessary to gradually add the acrylic emulsion to the amine resin adhesive that is being stirred as described above. That is, when an amino resin adhesive is added to an acrylic emulsion, it is difficult to obtain a good quality product.

[Examples] Hereinafter, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited to these examples unless the gist of the invention changes. In the following, parts and percentages are based on weight unless otherwise specified.

Examples 1-2 Using a reaction tank equipped with a stirrer, a reflux condenser and a thermometer,
Using the raw materials and alkali catalyst shown in Table 1, the reaction was carried out under the conditions shown in Table 1, and then cooled to room temperature to obtain 1000 parts of each amino resin adhesive. The physical properties were as shown in Table 1.

In addition, 1200 parts each of deionized water to which 1 part of sodium dodecylhenzenesulfonate was added as an emulsifier was charged into a reaction tank similarly equipped with a stirrer, a reflux condenser, and a thermometer, and then persulfuric acid was added as a polymerization initiator. 5 parts each of potassium were added. Thereafter, the deionized water was heated to 70°C while being stirred. Further, in deionized water maintained at the above temperature and stirred, II! shown in Table 2 is added. A mixture of acrylic monomer and dodecyl mercaptan (chain transfer agent) in an amount of I got it.

Next, in a container equipped with a stirrer, add the amino resin adhesive obtained by the above method as shown in Table 3, add the acrylic emulsion obtained by the above method in the amount shown in Table 3,
After addition at a rate that does not cause addition shock (500 parts/sin), a 25% aqueous sodium hydroxide solution was added to adjust the pH to 10.0, and stirring was continued for another 10 minutes to prepare the amino acid of the present invention. 100 parts of a resin adhesive composition was obtained. The physical properties of this amine resin adhesive composition were as shown in Table 3.

In addition, in Table 3, the fluidity was measured by the following method. That is, when 10g of a sample is taken into a test tube with a diameter of 18mm and a length of 180av, and the test tube is held horizontally at a temperature of 25°C, the flow of the sample is 15III per minute.
If it was within II, it was rated as no fluidity (×), if it exceeded 15 mm and within 5 mm, it was graded as poor (Δ), and if it exceeded 50II11, it was graded as good (0).

Example 3 Using the reaction tank used in Example 1, a reaction was carried out under the conditions shown in Table 1 using the raw materials and alkali catalyst shown in Table 1, and then the pH was adjusted to 5 with a 50% aqueous acetic acid solution. When the viscosity of the reaction solution reaches 1.5 poise/at25°C, add sodium hydroxide solution with a concentration of 25%. 8 liquid was added to neutralize the mixture, and the mixture was further cooled to room temperature to obtain 1000 parts of an amine resin adhesive having the physical properties shown in Table 1.

In addition, an acrylic emulsion with the physical properties shown in Table 2 was prepared in the same manner as in Example 1 except that the reaction tank used in Example 1 was used and the fI of the acrylic monomer and the amount used were changed to those shown in Table 2. I got it.

Next, the amino resin adhesive and acrylic emulsion obtained by the above method were placed in a container equipped with the stirrer used in Example 1, and the amino resin adhesive 100 of the present invention was prepared in the same manner as in Example 1. I got the department.

The physical properties of the obtained amino resin adhesive composition were as shown in Table 3.

Example 4 As in Example 3, using the raw materials and alkali catalyst shown in Table 1, the reaction was carried out under the conditions shown in Table 1, and then the concentration was 25.
% hydrochloric acid aqueous solution to 5.0, and further heated at 80'C.
After reacting for 1 hour, an aqueous sodium hydroxide solution with a concentration of 25% was added to neutralize the mixture, and the mixture was cooled to room temperature to obtain 1000 parts of an amino resin adhesive having the physical properties shown in Table 1.

Further, in the same manner as in Example 3, an acrylic emulsion having the physical properties shown in Table 2 was obtained in exactly the same manner as in Example 1, except that the type and amount of acrylic monomer used were changed to those shown in Table 2.

Next, in the same manner as in Example 3, the amino resin adhesive obtained by the above method and the acrylic emulsion were used to obtain 100 parts of the amino resin adhesive of the present invention.The obtained amino resin adhesive composition The physical properties of were as shown in Table 3.

Example 5 Using the reaction tank used in Example 1, the raw materials shown in Table 1, excluding melamine, and an alkali catalyst with a concentration of 2
Using 2 parts of 5% aqueous sodium hydroxide solution at a temperature of 8.
After incubating at 0°C for 40 minutes, this was further treated with a concentration of 25%.
% sodium hydroxide and melamine in the amount shown in Table 1 were added, reacted at 80°C for 30 minutes, and then cooled to room temperature to obtain an amino resin adhesive with the physical properties shown in Table 1. .

Further, an acrylic emulsion having the physical properties shown in Table 2 was obtained in exactly the same manner as in Example 1, except that the type and amount of acrylic monomer used were changed to those shown in Table 2.

Next, in the same manner as in Example 1, 100 parts of an amino resin adhesive composition of the present invention was obtained using the amino resin adhesive obtained by the above method and the acrylic emulsion. The physical properties of the obtained amino resin adhesive composition were as shown in Table 3.

Example 6 40 each of the amino resin adhesives obtained in Example 1 and Example 3
80 parts of an amino resin adhesive having the physical properties shown in Table 1 were obtained by stirring and mixing at 25° C. for 10 minutes.

In addition, 10 parts each of the acrylic emulsions obtained in Example 2 and Example 3 were stirred and mixed at 25°C for 10 minutes.
20 parts of an acrylic emulsion having the physical properties shown in the table was obtained.

Next, 80 parts of the amino resin adhesive obtained above and 20 parts of the acrylic emulsion were stirred and mixed in the same manner as in Example 1 to obtain the amino resin adhesive composition 100 of the present invention having the physical properties shown in Table 3. I got the department.

Reference Examples 1 to 6 Commercially available rock wool specified in JIS A-9504 was dispersed in water at 1%, and this was made into a paper using the same method as paper making, with a length of 300 mm, a width of 3001 mm, and a thickness of 9 mm, containing water. A wet rock wool board with a content of 50 to 60% was obtained.

Next, 1000 g of each of the amino resin adhesive compositions of the present invention obtained in Examples 1 to 6 were diluted with deionized water so that the resin solid content was 5%, using a spray gun. It was applied uniformly onto the wet rock wool plate and filtered under suction at a pressure of 60 Torr. Thereafter, this rock wool board was placed in a hot air circulation dryer and dried and cured at a temperature of 200°C for 2 hours to obtain a product rock wool board.

The physical properties (degree of yellowing and fish odor, bending strength, heat deflection resistance) of each rock wool board and the amount of formaldehyde released during drying were measured. The results are shown in Table 4, and the product quality was satisfactory, and the amount of formaldehyde released during drying had almost no adverse effect on the working environment.

The physical properties shown in Table 4 were measured by the methods listed below.

1) Yellowing degree: The whiteness is measured using a color difference meter, and those showing a value of 0.95 or more compared to the blank (molded and dried with only rock wool without using an amino resin adhesive composition) are ○.
, those showing a value of 0.90 or more and less than 0.95 are △, 0.
Those showing a value of less than 90 were marked as ×.

2) Odor purification: Those who detected a fishy odor or a R4Ql-based odor from the product were evaluated as ×, and those that were not detected were evaluated as O.

3) Bending strength: product vertically 60III11, horizontally 15nu+
(Thickness remains 9m) to make a test piece, and this test piece is loaded using a universal testing machine (Autograph manufactured by Shimadzu Corporation) at a loading speed of 10m + * / + gin, , span 4
The fracture load (g-f) measured under the conditions of 01 is shown.

4) Heat resistance deflection: The product was cut into a width of 50IIIl (the length and thickness were 30hm and 9mmw) to obtain a test piece, and one end of this test piece 1 was fixed with a fixed needle 3 on the wooden fixed stand shown in Fig. 1. Fix it with. Thereafter, the XsE test piece 1 fixed on the fixing table 2 was left horizontally in a hot air circulation dryer at a temperature of 100°C for 1 hour, and the sinking of the tip of the test piece 1 was measured and determined as heat deflection. .

5) Amount of formaldehyde released during drying;
After 90 minutes and 120 minutes, samples are taken using Kita-type detection tubes and the formaldehyde content is measured. If the maximum value is 3 ppm or less, ○, if it exceeds 3111311 and 10 pp- or less, Δ, 10 ppm. Those exceeding the above are marked as × Comparison Reference Examples 1 to 4 Except for using the amino resin adhesive obtained in Example 1, Example 3, Example 4, and Example 5 (without the addition of acrylic emulsion) Product rock wool boards were obtained in exactly the same manner as in Examples 1 to 6.

The physical properties of each rock wool board and the amount of formaldehyde released during drying of the rock wool board were measured in the same manner as in Reference Examples 1 to 6.

The results are shown in Table 5, and the physical properties of the product rock wool were not satisfactory compared to those using the amino resin adhesive composition of the present invention. Furthermore, the amount of formaldehyde released during drying of the rock wool board showed a value that was problematic for the working environment.

Comparative Reference Example 5 The amino resin adhesive obtained in Example 2 (without the addition of acrylic emulsion) and the acrylic emulsion obtained in Example 1 were mixed in a weight ratio of 1 in the same manner as in Examples 1 to 6. Product rock wool boards were obtained in exactly the same manner as in Reference Examples 1 to 6, except that an amino resin adhesive composition obtained by mixing at a ratio of :1 to 1 was used. The physical properties of this rock wool board and the amount of formaldehyde released during drying of the rock wool board were measured in the same manner as in Reference Examples 1 to 6. The results are shown in Table 5. 1. Unless an amino resin adhesive having the composition specified in the present invention is used, the heat resistance of the rock wool product deteriorates. Moreover, the fluidity of the amine resin adhesive composition also deteriorates.

〔Effect of the invention〕

As explained in detail above, the amino resin adhesive composition of the present invention is made by containing an amino resin adhesive and an acrylic emulsion in a specific ratio, and is a suitable adhesive for manufacturing rock wool boards. be. That is, conventionally, amino resin adhesives have been exclusively used in the production of rock wool boards, but when such adhesives are used, the resulting rock wool boards turn yellow, have a fishy odor, and the rock wool During the heating and curing process of rock wool boards during board manufacturing, free formaldehyde contained in the adhesive is released into the atmosphere, which poses a problem in that it worsens the working environment.

On the other hand, when a rock wool board is manufactured using the amino resin adhesive composition of the present invention, the fluidity of the adhesive composition is good as shown in each example. It has a long life and is easy to work with when manufacturing rock wool boards. Furthermore, as shown in the reference examples, the obtained rock wool board does not yellow, has very little fishy odor, and formaldehyde odor during the heating and curing process of the rock wool board does not pose a problem. ,
It is an extremely excellent adhesive for producing rock wool boards.

Furthermore, the amino resin adhesive composition of the present invention can be suitably used as other adhesives such as adhesives for producing plywood, for example.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a test method for a test piece of a heat resistance deflection test of a product rock wool board in a reference example and a comparative reference example. In the figure, 1----------1 test piece, 2------, - fixed base, 3-------1 fixed needle, are shown. Patent applicant Mitsui Toatsu Chemical Co., Ltd.

Claims (1)

[Claims] An amino resin adhesive composition characterized in that the amino resin adhesive contains 2.0 to 30.0 parts by weight of an acrylic emulsion as a solid content based on 100 parts by weight of the solid content of the amino resin adhesive.