JPH0699172B2 - Cement composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a cement composition. More specifically, specific ethylene-tertiary fatty acid vinyl ester-
By incorporating a vinyl acetate copolymer emulsion into the cement composition, it has excellent flexibility, adhesiveness and durability, and is a finishing material as a durability improving material for concrete structures,
The present invention relates to a cement composition that can be used as a waterproof material, a ground control material, an adhesive, and the like.

<Prior art> Cement concrete structures have been widely used in the civil engineering and construction fields for semi-permanent durability since ancient times, but in recent years, neutralization of concrete structures, cracks, salt damage by aggregates, and alkaline bones. The problem of early deterioration of concrete due to material reaction is highlighted. A variety of durability-improving protective materials, repairing materials, and repairing materials have been studied for these problems, and one of them is expected to be polymer cement mortar capable of following concrete cracks. Conventionally known polymer cement mortar is a mixture of synthetic resin emulsion synthetic rubber latex and the like in cement mortar in order to improve adhesion, bending, tensile strength and watertightness, airtightness, wearability, etc. Among them, among synthetic resin emulsions, ethylene-vinyl acetate copolymer resin emulsions are used in large quantities because they have excellent compatibility with cement and excellent adhesion to various substrates.
However, these materials have not reached the level of flexibility and elongation that can follow cracks in concrete.

In Japanese Patent Publication No. 47-33054, the content of vinyl acetate component is 60
A modified cement product is proposed in which -90% by weight of an ethylene-vinyl acetate copolymer emulsion is mixed with cement in a proportion of 2 to 40% by weight as a resin solid content. In such a cement composition, the ability to follow cracks cannot be imparted, and the elongation of the coating becomes extremely small, especially at low temperatures, and it cannot be used.

Moreover, in Japanese Patent Publication No. 52-25406, the ethylene content is 5
-17% by weight, C9-10 branched fatty acid vinyl ester content 2-30% by weight, vinyl acetate content 95-53% by weight
And a cement composition prepared by kneading an aqueous emulsion of a copolymer having a transition temperature in the range of 15 ° C to -15 ° C with cement and optionally a filler and water. ing.

Furthermore, in Japanese Examined Patent Publication (Kokoku) No. 55-19912, an ethylene content of 12 using a specific polyvinyl alcohol as a protective colloid
-30% by weight, content of tertiary aliphatic monocarboxylic acid ester of 0.5 to 30% by weight, and the balance comprising a copolymer dispersion of primary aliphatic monocarboxylic acid vinyl ester mixed with cement for use in cement mortar There is an illustration of the composition.

Even if such an ethylene-tertiary fatty acid vinyl ester-vinyl acetate copolymer emulsion is used, the crack followability is poor, and the elongation of the film is small at low temperatures, so that sufficient improvement effects have not been obtained.

Further, Japanese Patent Publication No. 57-43546 discloses that a vinyl acetate-ethylene-normal butyl acrylate or 2-ethylhexyl acrylate (50-95 / 4-49.5 / 0.5-45% by weight) copolymer emulsion is used as a solid component for cement. There is a proposal for a cement product containing 1 to 30% by weight. Also with respect to such a cement product, crack followability, elongation of the film at low temperature, etc. are hardly improved, and they are not usable for the purpose of the present invention.

<Problems to be Solved by the Invention> In view of the above circumstances, problems to be solved by the present invention,
That is, the object of the present invention is, when preparing a cement composition, high flexibility and elongation that allows the cement hardened material to follow concrete with less mixing of air bubbles, and further, the influence of those temperatures is small, and the adhesive strength is further excellent. It is to provide a cement composition.

<Means for Solving Problems> In the present invention, 5 to 30% by weight of ethylene, 30 to 65% by weight of a tertiary fatty acid vinyl ester having 9 to 11 carbon atoms, and 15% of vinyl acetate are used.
A cement characterized by mixing 40 to 150 parts by weight of an ethylene-tertiary fatty acid vinyl ester-vinyl acetate copolymer emulsion having a composition of ˜55% by weight with respect to 100 parts by weight of cement as a resin solid content. It relates to the composition.

The ethylene-tertiary fatty acid vinyl ester-vinyl acetate copolymer emulsion of the present invention means 5 to 30% by weight of ethylene, 30 to 65% by weight of tertiary fatty acid vinyl ester, and 15 to 55% by weight of vinyl acetate. , Preferably ethylene 10-25
It has a composition of 35% by weight, 35 to 60% by weight of tertiary fatty acid vinyl ester, and 20 to 50% by weight of vinyl acetate.

When ethylene content is less than 5% by weight, tertiary fatty acid vinyl ester is less than 30% by weight and / or vinyl acetate is more than 55% by weight, flexibility to follow cracks in concrete when the copolymer emulsion is mixed with cement Hardened cement with

Further, when the ethylene content exceeds 30% by weight, the tertiary fatty acid vinyl ester content exceeds 65% by weight, and / or the vinyl acetate content is less than 15% by weight, the cohesive force of the polymer is weakened, so that it is mixed with cement. At this time, it is not preferable because it becomes impossible to follow the cracks in the concrete or the adhesive force is reduced.

The tertiary fatty acid vinyl ester used in the present invention is
Vinyl ester of branched fatty acid having 9 to 11 carbon atoms, generally
Expression(R in the formula₁， R₂And R₃Is a linear alkyl group)
The compound is shown. Typical compounds have 9 to 11 carbon atoms
Esters of versatic acid, a synthetic fatty acid
(Specifically, 10, Beova 9. Ciel Chemistry
Manufactured) is exemplified. Ethylene used in the present invention-C9
~ 11 tertiary fatty acid vinyl ester-vinyl acetate copolymerization
For the production of body emulsion, vinyl
Esters such as vinyl propionate and vinyl laurate
30% by weight or less in the above copolymer polymer component
Can be copolymerized.

Further, vinyl halide represented by vinyl chloride, 2-ethylhexyl (meth) acrylate, n-butyl (meth)
A copolymerizable monomer such as (meth) acrylic acid ester represented by acrylate, ethyl (meth) acrylate, methyl (meth) acrylate, etc., crotonic acid ester, itaconic acid ester, etc. within the range that does not impair the effects of the present invention. It is also possible to copolymerize two or more species in an amount of 20% by weight or less.

Further, a carboxyl group-containing monomer such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid (including half ester), maleic acid (including half ester) and its anhydride, N-methylol acrylamide, N-hydroxymethylol acrylamide, etc. N-methylol derivative monomer of 2-hydroxyethyl (meth) acrylate, 2
-Hydroxyl group-containing monomer such as hydroxypropyl (meth) acrylate, dimethylaminoethyl methacrylate,
Amino group-containing monomer such as dimethylaminopropyl acrylamide Glycidyl (meth) acrylate, epoxy group-containing monomer such as allyl glycidyl ether, amide group-containing monomer such as acrylamide, methacrylamide, maleinamide, sodium vinyl sulfonate, methallyl sulfonic acid Sulfonyl group-containing monomers such as soda and 2-acrylamido-2-methylpropanesulfonic acid, and diallyl phthalate, triacrylate, tetraacrylate, triallyl cyanurate, triallyl isocyanurate, polyvinyl vinyl monomers such as divinylbenzene, etc. One or more selected from the group may be copolymerized in the range of 0 to 10% by weight for the purpose of improving various other physical properties such as water resistance, solvent resistance, weather resistance and heat resistance.

Examples of the dispersion stabilizer used when producing the ethylene-tertiary fatty acid vinyl ester-vinyl acetate copolymer emulsion used in the present invention include protective colloids, nonionic surfactants, anionic surfactants and amphoteric surfactants. 1 of etc.
It is possible to use one kind or two or more kinds.

Examples of protective colloids that can be used include partially saponified polyvinyl alcohol, fully saponified polyvinyl alcohol, sulfonic acid modified polyvinyl alcohol, carboxy modified polyvinyl alcohol, silanol group-containing polyvinyl alcohol and other polyvinyl alcohols, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, and the like. Cellulose derivatives are exemplified.

Examples of the nonionic surfactant include polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, oxyethylene / oxypropylene block copolymer, sorbitan fatty acid ester, polyoxyethylene fatty acid ester, and polyoxyethylene sorbitan fatty acid ester. .

Examples of the anionic surfactant include an alkyl sulfate ester salt, an alkylbenzene sulfonate, an alkylsulfosuccinate, an alkyldiphenyl ether disulphonate, a polyoxyethylene alkali sulfate, and a polyoxyethylene alkyl phosphate.

When producing the ethylene-tertiary fatty acid vinyl ester-vinyl acetate copolymer emulsion used in the present invention, the polymerization initiator used is represented by ammonium persulfate, sodium persulfate, potassium persulfate, hydrogen peroxide and the like. An oily radical initiator such as an aqueous radical initiator, an organic peroxide or an azo compound can be used.

In the polymerization, it is more preferable to use a so-called redox catalyst system in which a reducing agent is used in combination with the polymerization initiator.

As the reducing agent used at that time, longalit (formaldehyde sulfoxylate), sodium thiosulfate, sodium sulfite, sodium hyposulfite, L-ascorbic acid and its salt, succinic acid and its salt, ferrous sulfate, cuprous chloride, etc. are emulsified. Any of those generally used in polymerization can be used.

As a method for producing the ethylene-tertiary fatty acid vinyl ester-vinyl acetate copolymer used in the present invention, any known method such as batch polymerization method and continuous polymerization method can be used. A good emulsion can be obtained by appropriately selecting optimal conditions such as various raw materials such as a backbone monomer, a modified monomer, a dispersion stabilizer, a polymerization initiator (including a reducing agent in the case of a redox catalyst system), a polymerization temperature and a reaction time. To be

The cement composition in the present invention has a resin solid content of 4 parts by weight based on 100 parts by weight of the above-mentioned ethylene-tertiary fatty acid vinyl ester-vinyl acetate copolymer emulsion.
Those mixed with 0 to 150 parts by weight are preferred.

If the cement composition is used in which the resin solid content is less than 40 parts by weight, it is not preferable because it does not have the property of being able to follow cracks generated at a later date.

In a cement composition having a resin solid content of more than 150 parts by weight, the adhesive strength is reduced and the cost is increased, resulting in poor economic efficiency.

The cement composition in the present invention comprises cement and ethylene-
In addition to the tertiary fatty acid vinyl ester-vinyl acetate copolymer emulsion, aggregates such as mountain sand, river sand and silica sand generally used for cement compositions, fillers such as calcium carbonate, calcium hydroxide and stone powder, glass fiber, A fibrous substance such as steel fiber, carbon fiber, or plastic fiber, a fluidizing agent, a water reducing agent, a waterproofing agent, an antifoaming agent, or the like can be mixed depending on the use and workability.

As the cement in the present invention, any cement generally used in the field of civil engineering and construction such as ordinary Portland cement, white Portland cement, early strength Portland cement, moderate heat Portland cement, alumina cement and mixed cement can be used.

<Examples> The physical properties of the following Examples and Comparative Examples were measured as follows.

(1) Zero span elongation (mm) Resin solid content of emulsion is 70 parts by weight as resin solid content based on 100 parts by weight of cement of powder (Portland cement / silica sand 7 / silica sand 8 = 100/75/75 weight ratio). The mortar, which was added and kneaded so as to be the same as above, was applied to a V-cut slate plate to a coating thickness of 2 mm (wet) and a width of 50 mm, and air-dried for 2 weeks.

This product is subjected to a tensile test at a tensile speed of 2 mm / min, and the elongation (mm) until a crack occurs in the mortar layer is measured as a zero span elongation.

It can be said that the larger the elongation, the better the followability to the cracks in the concrete and the better the result.

(2) Adhesive force (kgf / cm ² ) Prepare mortar in the same manner as in zero-span elongation, apply it to a mortar board (7 × 7 × 2 cm) to a thickness of 2 mm (wet), and perform air-drying curing for 2 weeks.

An iron attachment (4 x 4 cm) is set on this with an epoxy adhesive, and the adhesion force by plane tension is measured with a Kenken tensile tester.

The higher the adhesion, the better.

(3) Elongation (%) of mortar sheet Knead the resin solid content of the emulsion and Portland cement so that the weight ratio is 100/100, and apply 2 mm (we
It was smeared on t) and air-cured for 2 weeks to prepare a mortar sheet. Cut this sheet into strips with a width of 10 mm,
A tensile test is conducted at a tensile speed of 200 mm / min at temperatures of -10 ° C 23 ° C and 60 ° C.

The larger the elongation at each temperature level, the better.

Example 1 The following materials were placed in a 5 l stainless steel autoclave equipped with an anchor type stirrer.

Polyvinyl alcohol (saponification degree 88 mol%, degree of polymerization 170
0) ‥‥‥‥ 50g Polyoxyethylene nonylphenol ether (HLB = 1
3.7) ‥‥‥‥‥‥‥‥‥‥‥ 20g Ion-exchanged water ‥‥‥‥‥‥‥‥‥‥‥‥‥‥ 900ml Acetic acid ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ Ichitetsu ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ 0.02g Vinyl acetate ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ 600g Versatic vinyl ester (Veova 10, shellization
(Gakusei) 600g After thoroughly replacing the air in the autoclave with ethylene,
Raise the temperature to 50 ° C and add 40 kg / cm of ethylene.²The temperature was raised to.

Then, 400 ml of 3% ammonium persulfate aqueous solution and 200 ml of 3% aqueous solution of Rongalit were added for 5 hours for polymerization. The cooling temperature was adjusted so that the polymerization temperature during the polymerization was 50 ° C.

The unreacted monomer mainly consisting of ethylene was removed from the emulsion after the polymerization to obtain a product emulsion.
The obtained emulsion had a solid content of 50.0%, and coarse particles that could not be filtered through a 100-mesh wire mesh were 15 ppm, which was a good emulsion.

Table 1 shows the results of evaluation of the above items using this emulsion.

Those in which the ethylene set pressure as shown in Example -2 Example -1 and 40 kg / cm ² was changed to 50 kg / cm ^2. Other conditions are in Example-1.
Is the same as

The physical properties of the produced emulsion are as follows: solid content 51.4%, coarse particles 18
It was as good as ppm. The results of evaluation of the above items using this emulsion are shown in Table 1.

Example-3 In Example-1, 600 g of vinyl acetate, Veova Uses 10 600g
Place 495g vinyl acetate, Veova Changed to 10 705 g
It was The other conditions are the same as in Example-1.

The physical properties of the emulsion produced are: solid content 50.0%, coarse coarse particles 17pp
It was good with m. The results of evaluation of the above items using this emulsion are shown in Table 1.

Comparative Example-1 Veova in Example-1 Vinyl acetate 1200 without 10 at all
g and other conditions are the same as in Example-1
Manufactured.

The obtained emulsion has a solid content of 50.1% and coarse particles of 20 pp.
m showed a good emulsion state.

However, Baoba This emaljo that does not use 10 at all
As a result of evaluating the above-mentioned items,
And the elongation of the mortar sheet is remarkably inferior and cannot withstand use.
It was judged to be bad.

Other conditions were changed in Comparative Example -2 Comparative Example 1 Ethylene set pressure from 40 kg / cm ² to 75 kg / cm ² were the same as Comparative Example 1.

The obtained emulsion has a solid content of 58.0% and coarse particles of 35 ppm.
And showed a good emulsion state.

In this Comparative Example-2, whether or not the performance which was insufficient in Comparative Example-1 can be improved by increasing the ethylene copolymerization amount was examined.

The evaluation results of Comparative Example-2 are shown in Table-1. As a result, the effect of improving the zero-span elongation and the mortar sheet elongation characteristics is insufficient by simply increasing the ethylene copolymerization amount.

Comparative Example-3 In Example-1, 600 g of vinyl acetate, Veova Uses 10 600g
Octopus with vinyl acetate 990g, Veova Changed to 10 210g
It was The other conditions were the same as in Example-1.

The physical properties of the resulting emulsion are 50.1% solids and 20 ppm coarse particles.
And a good emulsion was obtained.

This comparative example-3 is 10 The amount of baoba of the present invention
10 When the amount used is below the lower limit, it is evaluated as a mortar composition.
When set to zero, zero span elongation and mortar sheet elongation
, Is insufficient, especially at low temperatures.

Comparative Example-4 Veova in Example-2 Change to 10 600 g, 2-ethylhex
600 g of sil acrylate was used. Other conditions are implemented
Same as Example-2.

The physical properties of the emulsion produced are: solid content 51.2%, coarse particles 300p
pm and became an emulsion with many coarse particles.

This Comparative Example-4 was prepared by adding 2-ethylhexyl acrylate.
Beova Used instead of 10 vaoba Get the same effect as 10.
Although it was examined whether or not it is possible,
The value results show that both zero span elongation and mortar sheet elongation
It was extremely inferior and could not be used.

Comparative Example-5 Polymerization was carried out in Example-1 without using ethylene. The other conditions are the same as in Example-1.

The physical properties of the produced emulsion are as follows: solid content 46.2%, coarse particles 25
The emulsion was as good as ppm.

Comparative Example-5 illustrates the case where ethylene, which is an essential component of the present invention, is not used at all. That is, in the physical properties of the mortar composition shown in Table-1, Comparative Example-5 has insufficient performance in both zero span elongation and mortar sheet elongation.

Comparative Example-6 In Example-1, 600 g of vinyl acetate, Veova Used 10 600 g
However, 113 g of vinyl acetate and Veova Changed to 10 1087g
It was The other conditions are the same as in Example-1.

The physical properties of the emulsion produced are: solid content 50.0%, coarse particles 40ppm
It was a good emulsion.

In Comparative Example-6, The amount of use is 10
10 When the usage amount is exceeded, the resin skeleton becomes flexible.
Because it is too much, both zero span elongation and mortar sheet elongation
It shows that the performance is degraded.

<Effects of the Invention> From the performance comparison results of the above-mentioned Examples and Comparative Examples, 5 to 30% by weight of ethylene is added in order to impart crack followability when cement is mixed, elongation of the coating at low temperature, etc., which is the object of the present invention. Mixing ethylene-tertiary fatty acid vinyl ester-vinyl acetate copolymer emulsion containing 30 to 60% by weight of tertiary fatty acid ester having 9 to 11 carbon atoms and 15 to 55% by weight of vinyl acetate into the cement composition. It became clear that this can be achieved for the first time.

Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display area C04B 24:26) 2102-4G

Claims (1)

[Claims] [Claim 1] Ethylene ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ The ethylene-tertiary fatty acid vinyl ester-vinyl acetate copolymer emulsion having a composition of 15 to 55% by weight is added to 100 parts by weight of cement.
A cement composition comprising 40 to 150 parts by weight of a resin solid content.