JP2000070849A - Formation of surface layer consisting of mma-based resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control color fading and discoloration of the surface of a structural body such as the floor face and the sidewall or the like of a pool in which the structural body is immersed underwater in many cases. SOLUTION: An MMA-based monomer contains a light resistant stabilizer, an ultraviolet absorber and an MMA-based polymer soluble in MMA and contains 0.1-2 pts.wt. curing accelerator and 0.4-0.9 pts.wt. curing agent fused on 100 pts.wt. MMA-based monomer. A surface layer consisting of MMA-based resin is formed by performing application and hardening of the MMA-based monomer at least two or more times. Thereby, such color fading and discoloration are controlled that these are remarkably seen in the case of underwater- immersing a structural body coated by using usual acrylic-based monomer syrup.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface layer obtained by laminating MMA resins used in the fields of civil engineering and construction, and more particularly to protection of flooring materials, wall materials, road pavement and the like.
It relates to the surface layer used in the landscape business, in which fading is suppressed.

[0002]

2. Description of the Related Art MMA resins cure very quickly, cure even at low temperatures, and have excellent chemical resistance, abrasion resistance, impact resistance,
Because it has slip resistance, etc., regardless of new construction, repair and renovation, floors of general buildings, factories, warehouses, freezers, parking lots, roads, sidewalks, pedestrian bridges, promenades, road surface indication, water and sewer tanks, It is used for surface protection and landscape projects in various places such as swimming pools.

[0003] As a method of forming a surface made of such an MMA-based resin, conventionally, a primer is applied to secure an adhesive strength to a base, and then methyl methacrylate (MMA) and (meth) acrylic ester are applied. And a compound having a plurality of polymerizable double bonds is added as a crosslinkable component, and further, an MMA-based polymer having a solubility in these monomer mixtures, a plasticizer and other coloring agents, an antifoaming agent,
Stabilizer, hardening accelerator, etc. are added as needed, and the intermediate layer is applied by using the one with aggregate added as the one to form the main layer, and the surface layer is protected for the purpose of protecting the intermediate layer. Although application is performed, a method of applying a clear type resin which does not color the surface layer so as not to impair the color of the intermediate layer and does not contain a coloring agent or an aggregate is generally used.

[0004] The above resins are polymerized by redox polymerization using a peroxide curing agent as an oxidizing agent and a curing accelerator contained in the resin as a reducing agent, but the polymerization reaction is inhibited in the presence of oxygen. Therefore, in order to allow the polymerization reaction to proceed in the air, a paraffin wax for blocking air during the polymerization reaction is added to the resin. A curing agent and a curing accelerator are used. For example, the curing agent and the curing accelerator are each 1 to 100 parts by weight of the MMA monomer.
It is common to use 10 parts by weight.

[0005]

The MMA resin is inherently excellent in weather resistance, and is generally used for ordinary building floors, factories, warehouses, freezers, parking lots, roads, sidewalks, pedestrian bridges, promenades, road markings, etc. There is no problem with the surface exposed inside, but when the surface is buried in water after construction such as water and sewer tanks, pools, etc., from the MMA resin polymer applied and cured by the construction method described above, There is a problem that discoloration or fading occurs more rapidly than the surface that is exposed to the air.

The present inventors have conducted intensive studies to solve the above-mentioned problems. As a result, even when the surface is buried in water, a light-resistant stabilizer and an ultraviolet absorber are added to the MMA-based monomer to cure the surface. Accelerator, if the amount of the curing agent is defined in a certain range and at least two hardened surface layers are laminated,
It has been found that it is extremely effective in suppressing discoloration and fading of the surface having the MMA-based resin in the surface layer.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide a surface in which discoloration and fading are suppressed even when the surface is buried in water after completion of construction. is there. That is, the gist of the present invention is to provide a light stabilizer, an ultraviolet absorber and an MMA-based polymer soluble in MMA, and 0.1 to 2 parts by weight of a curing accelerator based on 100 parts by weight of the MMA-based monomer. A method of forming a surface layer made of an MMA resin, wherein applying and curing an MMA monomer containing 0.4 to 0.9 parts by weight of a curing agent is performed at least twice.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The MMA monomer as used in the present invention is a monomer mixture comprising methyl methacrylate and (meth) acrylate and a compound having a plurality of polymerizable double bonds as a crosslinkable component.

The (meth) acrylate used in the MMA monomer includes, for example, ethyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate, acrylic acid Examples include methyl, ethyl acrylate, n-butyl acrylate, i-butyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, and the like.

Examples of the compound having a plurality of polymerizable double bonds contained in the MMA monomer include ethylene glycol di (meth) acrylate, 1,2-propylene glycol di (meth) acrylate, and 1,3-butylene glycol. Di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, divinylbenzene, diallyl phthalate, triallyl phthalate, tri Examples include allyl cyanurate, triallyl isocyanurate, allyl (meth) acrylate, diallyl fumarate, and the like, and may be used as a mixture of two or more.

Examples of the (meth) acrylic polymer having solubility in the MMA monomer include a homopolymer of MMA, MMA and ethyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, and methacrylic acid. t
-Butyl, 2-ethylhexyl methacrylate, methyl acrylate, ethyl acrylate, n-butyl acrylate,
Copolymers with one or more monomers such as i-butyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate and the like can be mentioned. Hereinafter, the MMA monomer is referred to as MMA.
What melt | dissolved the type | system | group polymer is called acrylic type monomer syrup.

Examples of the light stabilizer used in the present invention include bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate and bis (1,2,2,6,6-pentamethyl-4-). Piperidyl) sebacate, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine. The amount of addition is not particularly specified,
In consideration of the effect of the addition and the economic efficiency, the amount is preferably 0.1 to 5 parts by weight based on 100 parts by weight of the acrylic monomer syrup.

The ultraviolet absorber used in the present invention includes:
For example, 2- (5-methyl-2-hydroxyphenyl) benzotriazole, 2- (3,5-di-t-butyl-2)
-Hydroxyphenyl) benzotriazole, 2-
(3,5-di-t-amyl-2-hydroxyphenyl)
Benzotriazole is mentioned. The amount of addition is not particularly limited, but considering the effect of the addition and the economic efficiency, 0.1 to 100 parts by weight of the acrylic monomer syrup is used.
It is preferably from 0.01 to 5 parts by weight.

The MMA monomer used in the present invention is usually cured within a range of -30 ° C. to 35 ° C. within 2 hours using a known redox catalyst comprising a combination of a curing agent and a curing accelerator. Various types of redox catalysts can be used. As the curing agent, any one may be used as long as it is an oxidizing agent used for a redox catalyst. Benzoyl peroxide, lauroyl peroxide, acetyl peroxide, di-t-butyl peroxide, cumene hydroxyper It is preferable to use organic peroxides such as oxides and ketone peroxides. Preferred examples of the organic peroxide include benzoyl peroxide.
Benzoyl peroxide is preferably in the form of a paste or powder diluted with an inert liquid or solid to a concentration of about 50% to avoid danger during handling.

As the curing accelerator, any reducing agent may be used as long as it is a reducing agent used in a redox catalyst, but it is preferable to use a naphthenate such as cobalt naphthenate or a tertiary amine. . As the tertiary amine, those in which at least one aromatic residue is directly bonded to a nitrogen atom are preferable, and in particular, N, N-dimethylaniline, N, N-dimethyl-p-toluidine, N, N- One or a combination of two or more of di (hydroxyethyl) -p-toluidine and N, N-di (2-hydroxypropyl) -p-toluidine is preferred.

In the present invention, the curability of an acrylic monomer syrup mixed with a curing agent, a curing accelerator, and other necessary additives has a preferable range. After the syrup is applied, the fluidity of the syrup is lost, leading to curing. Before that, there must be enough time (pot life) for the coating surface to be smoothed. If the pot life and the curing time are too short, the coating operation becomes difficult, and a good coating film cannot be obtained. In general, the amount of the curing agent and the amount of the curing accelerator are adjusted so that the necessary pot life is obtained according to the operation and the curing time is sufficiently short. The preferred working time is 10 to 30 minutes, and the preferred curing time is 20 to 90 minutes.

In the present invention, a preferable pot life of 10 to 10 is used.
In order to obtain 30 minutes and a preferable curing time of 20 to 90 minutes, it is necessary to adjust the amount of the curing agent and the amount of the curing accelerator in accordance with the temperature of the composition and the base temperature at the time of application.

The discoloration and fading when the surface having the MMA resin on the surface layer is buried in water after construction and left as it is is MM
This is due to discoloration and fading of the surface layer made of the A-based resin,
The resin laminated below the surface layer does not discolor or fade. The main cause of discoloration and fading is that the curing agent and the curing accelerator contained in the resin are exposed to ultraviolet rays. Therefore, in order to suppress discoloration and fading of the laminated MMA resin layer, a light-resistant stabilizer and an ultraviolet absorber are added to the MMA resin used for the surface layer, and the curing accelerator and the amount of the curing agent used are within a certain range. Must be specified.

When a large amount of a curing accelerator and a curing agent are used, the cured product turns yellow and the surface structure of the (meth) acrylic polymer undergoes discoloration and fading, and the amount of the curing accelerator and the curing agent used is small. And problems such as a slow curing time occur. In order to suppress the discoloration of the cured product while maintaining a preferable pot life and the curing time, the amount of the MMA-based monomer used for the surface layer should be 100 parts by weight. The amount of the curing accelerator used is 0.1 to 2 parts by weight, and the amount of the curing agent used is 0.4 to
Preferably it is 0.9 parts by weight.

Conventionally, when the surface layer is applied using an acrylic syrup, for example, a method of applying the coating layer at a thickness of 0.4 or 0.2 kg / cm ^{2 at} a time for the convenience of operation is generally used. However, in such an application method, MM
When the resin A is buried in water after construction, discoloration and fading cannot be suppressed. However, although the reason is unknown, it has been found that even if the finally obtained coating thickness is the same, it is possible to minimize the fading when the coating thickness per coating is reduced and the coating is repeated twice or more. .

The surface layer made of the MMA resin formed in the present invention is usually formed on a surface of an inorganic material such as concrete by applying a primer, forming an intermediate layer thereon, and then on the intermediate layer. As the primer used herein, a one-component solution obtained by dissolving a polymer in a solvent or a mixture of a solvent-free two-component base agent and a curing agent is used,
These primers are applied and polymerized and cured in the former case, and dried in the latter case to form a primer layer composed of a polymer. Examples of the polymer include an MMA resin, an epoxy resin, a urethane resin, an acrylic resin, a polyester resin, and a vinyl ester resin.

As the MMA resin primer and the intermediate layer coated on the primer, MMA, (meth) acrylate and a compound having a plurality of polymerizable double bonds as a crosslinkable component are added. (Meth) acrylic polymer which has solubility in liquid,
If necessary, a plasticizer, an antifoaming agent, a stabilizer, a curing agent, a curing accelerator, etc. are added, and those obtained by stirring and mixing are preferably used. After application, the mixture is cured to form a primer layer and an intermediate layer. . The intermediate layer may be a single layer or two or more layers. The amount of the curing agent and the curing accelerator used for forming the primer layer and the intermediate layer is different from the case of forming the surface layer, and conventionally, the same amount as that used when forming the MMA-based resin layer by coating and curing may be used. it can.

The intermediate layer may or may not contain a colorant. When the intermediate layer contains a colorant, the colorant used is an inorganic pigment generally used as a civil engineering and construction material, specifically, titanium oxide, zinc oxide, chrome green, ultramarine, carbon black, and the like. And one or more of these are used. When adding the colorant, the powder may be added as it is, but for uniform coloring in a short period of time, a highly dispersed acrylic monomer syrup should be added in advance to achieve a predetermined concentration. Is preferred.

When the colorant is dispersed in the acrylic monomer syrup at a high concentration in advance, the colorant varies depending on the color, but it is generally used by dispersing 50 parts by weight of a powder pigment as a colorant into 50 parts by weight of the acrylic monomer syrup. It is a target. In the case of using a colorant, if the use of the colorant is small, the base cannot be completely hidden, and the purpose of using the colorant cannot be sufficiently achieved. The MMA used for the intermediate layer depends on the color because it may be damaged or cause poor curing.
The colorant dispersed in the acrylic monomer syrup is preferably 3 to 10 parts by weight based on 100 parts by weight of the resin.

The intermediate layer may or may not contain an aggregate, but when the aggregate is included, it is possible to easily give the surface structure a thickness. Examples of the aggregate contained in the intermediate layer include silica sand generally used as a material for civil engineering and construction, and colored aggregate obtained by calcining ceramic, and specifically, silica powder, differential silica sand, silica sand No. 8, silica sand 7 No. 6, silica sand No. 6, silica sand No. 5, ceramic sand and the like. One of these may be used, or a mixture of two or more thereof may be used.

On the intermediate layer thus formed, the above-mentioned acrylic monomer syrup defined in the present invention is applied and cured twice or more to form a surface layer in which discoloration and fading are suppressed. can do.

[0027]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.
In the following examples, bis (2,2) was used as a light stabilizer.
2,6,6-tetramethyl-4-piperidyl) sebacate and 2- (5-methyl-2-hydroxyphenyl) benzotriazole as an ultraviolet absorber are shown, but other light stabilizers and ultraviolet absorbers are shown. The same effect can be obtained by using.

Examples 1 to 6 and Comparative Examples 1 to 10 A slate plate 200 × 200 × 2 mm was used as a base.
On top of this, a primer (primer for ultra-make concrete) manufactured by Nitto Kagaku Kogyo KK as an MMA resin primer was formed with a brush to form a lowermost layer having a thickness of about 0.3 mm. Then, after the lowermost layer is cured, a mixture of 100 parts by weight of an acrylic monomer syrup (Nitto Chemical Industry Co., Ltd. resin for ultra-make frame color) and 50 parts by weight of powdered silica sand is mixed with a roller to a thickness of about 1 mm. It was then applied and cured to form an intermediate layer.

The intermediate layer thus formed has an MMA resin as an acrylic monomer syrup and a light stabilizer as bis (2,2,6,6-tetramethyl-4-piperidyl)
Sebacate, 2- (5-methyl-2) as an ultraviolet absorber
-Hydroxyphenyl) benzotriazole was added in the amounts shown in Table 1, and further as a curing agent and a curing accelerator.
Was applied in a coating thickness shown in Table 1 with a roller using the amount shown in Table 1 to form a surface layer. With respect to a laminate of two surface layers, the first layer was applied, and after the first layer was cured, the second layer was applied.

Each of the samples thus prepared was heated at 40 ° C.
It was exposed outdoors in water for 3 months, and the change in color was evaluated using a handy color tester (model H-CT, manufactured by Suga Test Instruments Co., Ltd.) in comparison with that before the outdoor exposure. Table 1 shows the results.

[0031]

[Table 1] In the table, light stabilizer, ultraviolet absorber, curing accelerator,
The addition amount of the curing agent indicates the addition amount (parts by weight) based on 100 parts by weight of the monomer in the acrylic monomer syrup. BPO of the curing agent is benzoyl peroxide, LPO is lauroyl peroxide, KPO is ethyl methyl ketone peroxide, DMA of the curing accelerator is N, N-dimethylaniline, DMT is N, N-dimethyl-p-toluidine,
HEP indicates N, N-di (hydroxyethyl) -p-toluidine.

From the results shown in Table 1, it can be seen that those out of the range of the present invention have a high degree of color change, while those according to the method of the present invention have little change in color when exposed to water and outdoors. .

[0033]

According to the method of the present invention, in the case where the surface layer is formed by laminating MMA resins in multiple layers, discoloration and fading can be suppressed even when the surface is buried in water.

Continuation of the front page (72) Inventor Yujiro Yoshii 4-160 Sunadabashi, Higashi-ku, Nagoya-shi, Aichi F-term in the Product Development Laboratory, Mitsubishi Rayon Co., Ltd. 4D075 AE15 CA50 DA06 DB12 DC02 EB22 EB56 EC37 EC47

Claims (1)

[Claims] An MMA-based monomer comprising a light-resistant stabilizer, an ultraviolet absorber and an MMA-based polymer soluble in MMA.
Applying and curing an MMA-based monomer containing 0.1 to 2 parts by weight of a curing accelerator and 0.4 to 0.9 parts by weight of a curing agent with respect to 00 parts by weight is performed at least twice. A method for forming a surface layer made of an MMA resin.