JPH04351671A - Aqueous emulsion of flame retarding resin and its production - Google Patents

Abstract

PURPOSE:To obtain the title emulsion which can give a film excellent in flame retardancy and resistance to thermal yellowing by adding a specified organic compound as a flame-retarding synergist to an aqueous emulsion of a specified halogenated copolymer. CONSTITUTION:The title emulsion is prepared by adding 0.1-5, per 100 pts.wt. copolymer, organic compound having a decomposition half-life of at least 2hr at 100 deg.C and forming free radicals (e.g. dicumyl peroxide) as a flame retarding synergist to an aqueous emulsion of a halogenated copolymer obtained by emulsion-polymerizing a monomer mixture of 10-40wt.% halogenated unsaturated monomer (e.g. vinylidene chloride) and 90-60wt. % unsaturated monomer copolymerizable therewith (e.g. methyl acrylate or butyl acrylate).

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is a flame-retardant resin useful as a backing agent for carpets, a binder or coating agent for paper, woven fabrics, non-woven fabrics, etc., an exterior paint for buildings, a repair paint for wallpaper, etc. The present invention relates to an aqueous emulsion and a method for producing the same.

0002

BACKGROUND OF THE INVENTION Aqueous resin emulsions are used as carpet backing agents, needle punch carpet binders, elastic paints, and various coating agents. This type of resin aqueous emulsion is often required to be flame retardant, as in the case of coating resin aqueous emulsions used for kitchen wallpaper, automobile interior materials, etc. The following were used as aqueous resin emulsions that required flame retardancy. ■ Water-based vinyl chloride resin or vinylidene chloride resin whose resin itself is flame retardant, such as vinyl chloride/vinylidene chloride copolymer, vinyl chloride/vinyl acetate copolymer, vinylidene chloride/acrylic acid alkyl ester copolymer, etc. Emulsion■ Aqueous emulsion of various resins containing flame retardants such as tetrabromobisphenol, antimony trioxide, trialkyl phosphate, hexabromocyclododecane, decabromodiphenyl oxide, and chlorinated phosphate ester.

[0003] However, the flame-retardant resin emulsion (①)
There are limitations to its use due to adhesion to adherends, film-forming properties, flame retardancy, weather resistance, thermal yellowing, etc. In addition, the aqueous resin emulsion containing the flame retardant described in (■) has a problem with the compatibility between the resin emulsion and the flame retardant. Poor compatibility causes separation of the flame retardant, and generally requires a large amount of flame retardant. As a result, there are drawbacks such as reduced adhesion to adherends and loss of texture.

JP-A-2-265973 discloses an aqueous resin obtained by adding 0.3 to 100 parts by weight of an organic halogen compound as a flame retardant to 100 parts by weight of an unsaturated monomer and carrying out emulsion polymerization. The emulsion contains as a flame retardant synergist a flame retardant synergist which has a decomposition half-life of more than 2 hours at a temperature of 100°C and is capable of forming free radicals. It describes an aqueous emulsion of a flame retardant-imparting resin in which the flame retardant resin is contained in an amount of 0.1 to 3 parts by weight. However, this flame retardant resin emulsion has insufficient flame retardancy due to the uneven distribution of the organic halogen compound used as the flame retardant, and a large amount of flame retardant is required to obtain sufficient flame retardancy. However, it has been found that there is a problem in that the resin turns yellow when a large amount of flame retardant is used.

[0005]

[Problems to be Solved by the Invention] The present invention has excellent flame retardancy when applied to or impregnated into fibrous materials, etc.
The present invention aims to provide an aqueous flame-retardant resin emulsion that can provide a film with excellent yellowing resistance, and also provides a method for advantageously producing the flame-retardant aqueous emulsion. It is.

[0006]

[Means for Solving the Problems] The aqueous flame retardant resin emulsion of the present invention comprises 1 halogen atom-containing unsaturated monomer.
An aqueous halogen-containing copolymer obtained by emulsion polymerization of a mixed monomer of 0 to 40% by weight and 90 to 60% by weight of an unsaturated monomer copolymerizable with the halogen atom-containing unsaturated monomer. The emulsion contains, as a flame retardant synergist, an organic compound (" This emulsion contains 0.1 to 5 parts by weight of a flame retardant synergist (referred to as a flame retardant synergist).

The flame retardant aqueous emulsion of the present invention contains 10 to 40 halogen atom-containing unsaturated monomers.
% by weight and 90 to 60% by weight of an unsaturated monomer copolymerizable with the same halogen atom-containing unsaturated monomer, the polymerization reaction system before the start of the polymerization, and after the start of the polymerization. It can be easily produced by adding 0.1 to 5 parts by weight of a flame retardant synergist to the polymerization reaction system before the completion of the polymerization reaction or to the resulting polymer emulsion after the completion of the polymerization reaction.

The flame retardant aqueous emulsion of the present invention contains a halogen atom as a flame retardant component and a flame retardant synergist compound in the halogen-containing copolymer resin as a binder component. By coating or impregnating various combustible materials such as carpets, textiles, wallpaper, and various combustible buildings with this resin emulsion, excellent flame retardancy can be easily imparted to those combustible materials. Furthermore, compared to an aqueous halogen-containing copolymer emulsion in which a flame retardant synergist compound is not used, the flame retardance of the film can be greatly improved.
It becomes possible to reduce the content of r), and as a result, the weather resistance and thermal yellowing resistance of the film can be significantly improved while maintaining the desired flame retardancy.

Examples of the halogen atom-containing unsaturated monomer used to obtain the flame retardant aqueous emulsion of the present invention include vinyl chloride, vinylidene chloride, vinyl bromide, vinylidene bromide, mono- or dichlorostyrene, Bromostyrene, chloroprene, etc., but from the viewpoint of copolymerizability with other unsaturated monomers, vinyl chloride,
Vinylidene chloride and chlorostyrene are preferred.

The halogen atom-containing unsaturated monomer is used in an amount of 10 to 40% by weight of the unsaturated monomer mixture. If the amount of halogen atom-containing unsaturated monomer is less than 10% by weight, the flame retardancy of the film will be insufficient, and if it exceeds 40% by weight, the yellowing of the film at high temperatures will be greatly reduced, so I also don't like it.

Examples of unsaturated monomers copolymerizable with the halogen atom-containing unsaturated monomer used in the present invention include vinyl acetate, acrylonitrile, methyl acrylate, ethyl acrylate, and n-acrylate from the viewpoint of weather resistance. propyl,
Isopropyl acrylate, ethylene, n-acrylate
Lower alkyl esters of acrylic acid such as butyl, iso-butyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, and the same lower alkyl esters of methacrylic acid as mentioned above are mainly used. These unsaturated monomers may include acrylic acid, itaconic acid,
Monomers having functional groups such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, acrylamide, and methylol acrylamide can be used together in a proportion of 10% by weight or less.

The type of unsaturated monomers, the combination of these unsaturated monomers, the copolymerization ratio, etc. in the present invention depend on the purpose and use of the resulting aqueous emulsion, and the glass transition point of the resulting resin. In consideration, it is appropriately selected within the above range. For example, if a product obtained by coating or impregnating an emulsion is required to have a soft texture, the glass transition point of the resulting resin should be -65 to -10°C.
selected to be. Further, when rigidity and shape retention are required, the glass transition point is selected to be 20 to 100°C. Further, the amount of the halogen atom-containing unsaturated monomer is selected depending on the flame retardance required.

Flame retardant synergists according to the invention are compounds which have a decomposition half-life of more than 2 hours at a temperature of 100° C. and which are capable of forming free radicals, such as, for example, dibenzyl. Benzene, benzyltriol, 1-phenyl 1,3,3-trimethylindane,
Examples include hydrocarbons such as biscumyl; organic peroxides such as di-t-butyl peroxide, dicumyl peroxide, and di-t-amyl peroxide.

In the present invention, the flame retardant synergistic agent is added to the aqueous halogen-containing copolymer emulsion, as described above, in the polymerization reaction system before the start of polymerization, in the polymerization reaction system after the start of polymerization and before the end of the polymerization reaction, Alternatively, it can be carried out by adding it to the resulting polymer emulsion after the completion of the polymerization reaction. For example, the synergistic agent may be dissolved in advance in the monomers to be polymerized, or the synergistic agent may be added directly to the emulsion before or after the polymerization reaction starts. Furthermore, it may be added later to the aqueous polymer emulsion obtained by emulsion polymerization. Further, the synergistic agent can also be added after being dissolved in an organic solvent such as toluene. In view of the dispersibility of the synergistic agent, it is desirable that the synergistic agent be present in the emulsion system during emulsion polymerization.

The flame retardant synergistic agent is added in an amount of 0.1 to 5 parts by weight, preferably 0.7 to 3.5 parts by weight, per 100 parts by weight of the halogen-containing copolymer. If the amount added is too small, the flame retardant synergistic effect will not be sufficiently obtained,
On the other hand, if the amount is too large, not only will the effect not be improved commensurately, but also the polymerization stability will be impaired if it is present in the emulsion polymerization system.

[0016] When the emulsion polymerization for producing the flame retardant aqueous emulsion of the present invention is carried out in the presence of a flame retardant synergistic agent in the emulsion polymerization system, the presence of the synergistic agent is necessary. Except for the fact that the polymerization is carried out at When adding an agent compound to a copolymer resin aqueous emulsion after emulsion polymerization, there is an essential difference between the conventional emulsion polymerization for producing this type of copolymer resin aqueous emulsion and the emulsion polymerization itself. do not have. That is, in the emulsion polymerization, a mixture of a halogen atom-containing unsaturated monomer and an unsaturated monomer copolymerizable with the unsaturated monomer is heated at an interface of sodium dodecylbenzenesulfonate or a sulfuric acid half-ster salt of p-nonylphenol. Emulsion polymerization is carried out in an aqueous medium in the presence of an activator and an initiator such as potassium persulfate and, if a flame retardant synergist is present in the emulsion polymerization system, the same synergist compound. let In addition, when the flame retardant synergistic agent is not present in the emulsion polymerization system, the synergistic agent is added to the aqueous polymer emulsion obtained by emulsion polymerization in an organic solvent such as toluene, as described above. Add it later by dissolving it.

The flame retardant aqueous resin emulsion of the present invention may optionally contain other resin aqueous emulsions (for example, various acrylic resin emulsions and ethylene-vinyl acetate emulsions) within the range that does not impair the physical properties of the resin film. copolymer resin emulsion, etc.) can be blended. In addition, flame retardants, polyvinylidene chloride emulsions, and the like can be added for the purpose of further improving flame retardancy. Furthermore, various additives such as plasticizers, antifoaming agents, antisettling agents, thickeners, antifreeze agents,
Lower alcohols, pigments, dyes, cement, aggregates, wetting agents, water repellents, texture control agents, crosslinking agents, antistatic agents, pH control agents, etc. can be blended.

[0018]

[Examples] Hereinafter, the present invention will be described in more detail by giving examples and comparative examples. All "parts" and "%" described in these examples are based on weight.

Example 1 Water was added to a reactor equipped with a temperature controller, a stirrer, a supply container, a thermometer and a nitrogen gas inlet pipe.
250
Part Sodium dodecylbenzenesulfonate
1 part potassium persulfate

After charging 1.6 parts, the inside was replaced with nitrogen gas, the pressure was then reduced, nitrogen gas was further introduced, and the pressure was reduced again.

Next, while maintaining the temperature inside the reaction vessel at 60° C. and stirring, vinylidene chloride was introduced into the reaction vessel from the supply vessel which had been replaced with nitrogen gas.
100 copies
methyl acrylate
200 copies
butyl acrylate
200 parts dicumyl peroxide
10 parts Sodium dodecylbenzenesulfonate
Part 10 Water

A mixture consisting of 250 parts was continuously fed in over 6 hours using a metering pump.

After the completion of supplying a predetermined amount of the mixture, polymerization was continued at 50° C. until the internal pressure of the reaction vessel reached 0 kg/cm 2 to produce an aqueous resin emulsion with a solid content of 50%. Table 1 summarizes the types and amounts of the raw materials used in Example 1, ie, unsaturated monomers, flame retardant synergists, and emulsifiers.

[0022] In addition, the stability of the resin aqueous emulsion obtained in Example 1 during polymerization, the stability of the resulting resin aqueous emulsion after storage at 40°C for one month, and the stability of the resin aqueous emulsion tested by the following method. The flammability and yellowing resistance of the film were as shown in Table 1.

■ Flammability test method Aqueous resin emulsion was applied and impregnated onto a needle-punch carpet made of polyethylene terephthalate with a basis weight of 320 g/m2 so that the solid content of the emulsion was 60 g/m2, and forced drying at 80°C. A needle punch carpet (sample) with fibers fixed with resin was obtained.

[0024] The combustion state and burning rate of the obtained sample were examined by the following method. That is, a width of 10
Take a sample piece with a diameter of 0 mm and a length of 350 mm and place it between U-shaped clamps. With the U-shaped clamp horizontal, the center of the tip of the Bunsen burner should be 2 points below the center of the opening of the test piece.
Place it so that it is at 0mm. Bunsen burner has an inner diameter of 1
Use a 0mm one, and adjust the burner flame to 40mm. A flame was applied to the test piece for 15 seconds to burn the test piece and flammability was evaluated according to the following criteria. Complete combustion...When the test piece burns up to a burning length of 254mm Self-extinguishing...When the test piece burns out before the burning length reaches 254mm

■ Heat yellowing test of film (accelerated test)
Method: An aqueous resin emulsion is applied onto a glass plate so that the dried film has a thickness of 100 μm, and dried at 60° C. for 5 hours. The obtained dried film was heated in an oven at 130° C. for 3 hours, and the degree of yellowing of the film was visually determined and evaluated on the following four scales. ◎…No discoloration ○…Slight yellowing △…Significant yellowing ×…Discoloration to brown

Examples 2 to 5 Various resin aqueous emulsions were produced according to the method described in Example 1 except that the raw materials used were changed as shown in Table 1. The stability, flammability and heat yellowing resistance of the resulting resin aqueous emulsion were tested in the same manner as in Example 1, and the results were as shown in Table 1.

[0027]

[Table 1]

Notes to Table 1: *1... Added to the emulsion polymerization system *2... The numerator indicates the amount added to the reactor, and the denominator indicates the amount added to the supply container.

Comparative Examples 1 to 3 Resin aqueous emulsions were prepared using the monomers listed in Table 1, without using any flame retardant synergist compounds, and otherwise following the method described in Example 1. did. The obtained aqueous resin emulsion was subjected to the same test as in Example 1. The results were as shown in Table 2.

Examples 6 to 7 The flame retardant synergist compound dicumyl peroxide (in the case of Example 6) was added to the aqueous resin dispersion obtained in Comparative Example 1.
, or biscumyl (in the case of Example 7) were each dissolved in 30 parts of toluene and added afterwards. The obtained aqueous resin emulsions were tested in the same manner as in Example 1, and the results are shown in Table 2.

[0031]

[Table 2]

Notes to Table 2: *2... The numerator indicates the amount added to the reactor, and the denominator indicates the amount added to the supply container. *3...Dissolved in toluene and added to an aqueous resin emulsion obtained by emulsion polymerization.

Comparative Examples 4 to 6 Aqueous resin emulsions were produced using the raw materials shown in Table 3, and in accordance with the method described in Example 1 except for the above. The obtained resin emulsions were tested in the same manner as in Example 1, and the results are shown in Table 3.

Comparative Example 7 The following raw materials were charged into the same reactor as in Example 1. water

200 parts 20 moles of ethylene oxide of p-nonylphenol 35% aqueous solution of sodium sulfuric acid half ester adduct (emulsifier A)

2.9 parts 25% aqueous solution of 25 mol ethylene oxide adduct of p-nonylphenol (emulsifier B)
20 copies

Next, after purging the inside of this reactor with nitrogen gas, the reactor was heated to 90° C. While keeping the inside of the reactor at this temperature, the following Feed I and Feed II were added in total amount over 3.5 hours. supplied.

Feed I Water

200 parts 35% aqueous solution of emulsifier A

29 parts Methyl acrylate

120 parts butyl acrylate

300 parts hexabromocyclododecane
80 parts bisque mill

Part 3

Feed II Water

85 parts potassium persulfate

2.5 parts

After the supply of Feed I and Feed II was completed, the mixture was further maintained at 90° C. for 2 hours for polymerization, and then the pH was adjusted to 7.6 with aqueous ammonia to obtain an aqueous resin emulsion. The obtained resin emulsion was tested in the same manner as in Example 1, and the results are shown in Table 3.

[0039]

[Table 3]

Notes to Table 3: *1...Added to the emulsion polymerization system. *2...The numerator indicates the amount added to the reactor, and the denominator indicates the amount added to the supply container. *4... As the emulsifier, a sulfuric acid half ester sodium salt of a 20 mole ethylene oxide adduct of p-nonylphenol and a 25 mole ethylene oxide adduct of p-nonylphenol were used.

[0041]

[Effects of the Invention] The aqueous resin emulsion of the present invention not only has a film that is excellent in flame retardancy, but also has excellent resistance to heat yellowing.

Claims (2)

[Claims] Claim 1: Halogen atom-containing unsaturated monomer 10-
In an aqueous emulsion of a halogen-containing copolymer obtained by emulsion polymerization of a mixed monomer of 40% by weight and 90 to 60% by weight of an unsaturated monomer copolymerizable with the same halogen atom-containing unsaturated monomer. , as a flame retardant synergist, an organic compound having a decomposition half-life of more than 2 hours at a temperature of 100° C. and capable of forming free radicals (“flame retardant”), based on 100 parts by weight of the halogen-containing copolymer. (referred to as "sexual synergist")
A flame-retardant aqueous emulsion containing 0.1 to 5 parts by weight of a flame-retardant resin. Claim 2: Halogen atom-containing unsaturated monomer 10-
40% by weight and 90 to 60% by weight of an unsaturated monomer copolymerizable with the same halogen atom-containing unsaturated monomer, the polymerization reaction system before the start of the polymerization, and after the start of the polymerization. The flame retardant-imparting resin according to claim 1, wherein 0.1 to 5 parts by weight of a flame retardant synergistic agent is added to the polymerization reaction system before the completion of the polymerization reaction or the resulting polymer emulsion after the completion of the polymerization reaction. Method for producing aqueous emulsion.