JPH11106215A - Surface-treated calcium carbonate powder, its production and resin composition compounded therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject powder capable of imparting moisture-curable one-pack resins with excellent thixotropy, slump resistance and storage stability by surface treatment of calcium carbonate powder so that its sedimentation degree determined by a specific method fall within a specified range. SOLUTION: This surface-treated calcium carbonate powder has such a requirement that its sedimentation degree determined by the method described below is <=10 mL: 70 mL of water at 25 deg.C is put into a stopper-bearing measuring cylinder 100 mL in volume followed by adding 7 g of calcium carbonate powder as sample to the water; the resulting mixture is vibrated for 15 min using a shaker 4 cm in amplitude and 320 cycles/min in frequency; after vibration, the mixture is left at rest for 10 min, and the apparent volume of the resulting sediment is read using the scale on the measuring cylinder and defined as sedimentation degree. The surface treatment agent is pref. a fatty acid ester which accounts for pref. >=70 wt.% of the whole surface treatment agent. The calcium carbonate to be used is pref. >=8 m<2> /g in BET specific surface area.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a surface-treated calcium carbonate powder, a method for producing the same, and a moisture-curable one-pack type resin composition obtained by blending the powder, and more particularly, to an excellent thixotropic property. Surface-treated calcium carbonate powder useful for moisture-curing one-pack type resins, which imparts slump resistance and good storage stability and hardly generates cracks and bubbles during curing, and a method for producing the same. And a moisture-curable one-pack type resin composition containing the powder.

[0002]

2. Description of the Related Art Moisture-curing one-pack resins are used in a wide variety of applications such as sealing materials, adhesives, flooring materials, and paints. Among these, sealing materials are widely used for purposes such as waterproofing and sealing in the fields of construction, automobiles, flooring and the like.
In these applications, the moisture-curing one-pack type resin composition (hereinafter, abbreviated as a one-pack type resin composition) does not require mixing the components of each of the two-package at the time of construction as compared with the two-pack type resin composition. Since there is a great advantage in construction such as no mixing technology is required and the working time can be shortened, the production volume is rapidly increasing. One-component resin compositions are often applied to vertical parts in applications such as jointing materials and sealing materials, and as a matter of course, it is necessary that the resin composition does not drip from application to curing. It must have high thixotropy and slump resistance, as it may affect workability during construction.

In order to impart these properties, colloidal silica, calcium carbonate, and the like have been conventionally used. However, at present, these thixotropy-imparting agents include many problems such as thickening during storage, foaming and cracking at the bonding interface during curing. For example, in colloidal silica, JP-B-45-41110,
Although many proposals have been made, such as Japanese Patent Publication No. 53-5899, and their superiority has been recognized, the disadvantage of this colloidal silica is that its modulus after curing is extremely high and its ability to follow the adherend is very high. It is difficult to finely adjust the viscosity due to poor thixotropy in a very small amount, it is difficult to adjust the viscosity delicately, the weather resistance is poor, there is a risk of silicosis, and it is difficult to handle in occupational hygiene.

[0004] In addition, in the case of calcium carbonate obtained by simply pulverizing and classifying raw limestone, which is generally called heavy calcium carbonate, coarse particles remain and the finished feeling is poor, and physical properties such as insufficient thixotropic property are not exhibited. Is enough
On the other hand, among the surface-treated calcium carbonates containing precipitated calcium carbonate, those in the category of the prior art include those having an initial thixotropy, but in a one-pack type resin composition that cures with moisture in the air. If the water adsorbed on the surface of calcium carbonate remains without being sufficiently removed, the reaction is started by the water, and the surface activity of general surface treatment agents such as alkali metal salts of fatty acids and resin acids, ABS, etc. In the case of those surface-treated with the agent, the reaction with these causes extreme deterioration of storage stability, foaming and cracking.

[0005] Among these, Japanese Patent Application Laid-Open No. 2-3830 / 1990.
9, a calcium carbonate surface-treated with a fatty acid ester has been proposed. According to this technique, the above-mentioned problems can be solved to a large extent, and the elongation of a sealing material, which is a typical one-pack type resin composition, can be considerably improved. An advantageous direction has been found. However, even in this technique, depending on the conditions at the time of surface treatment, physical properties such as thixotropy, storage stability and foaming may be insufficient, and further improvement is strongly desired at present.

[0006]

SUMMARY OF THE INVENTION In view of the above circumstances, the present invention satisfies excellent thixotropy and slump resistance and good storage stability by grasping certain characteristic values of surface-treated powder. Furthermore, in urethane, hardly any cracks or bubbles are generated during curing, a surface-treated calcium carbonate powder particularly useful for a moisture-curable one-pack type resin, a production method, and a moisture-curable one-pack type resin composition obtained by blending the same. Is provided.

[0007]

Means for Solving the Problems The present inventors have conducted intensive studies in an attempt to solve the above-mentioned problems, and as a result, have found that by using surface-treated calcium carbonate whose sedimentation degree measured by a specific method falls within a specific range. The present inventors have found that a one-pack type resin composition having excellent physical properties that solves the various problems described above can be obtained, and has completed the present invention.

That is, a first aspect of the present invention includes a surface-treated calcium carbonate powder characterized by having a degree of sedimentation of 10 ml or less according to the following measuring method. [Sedimentation degree] 70 ml of water at 25 ° C was placed in a 100 ml stoppered measuring cylinder.
And add 7 g of sample calcium carbonate powder. Using a shaker with an amplitude of 4 cm and 320 cycles / min, the resulting mixture is shaken for 15 minutes. After settling for 10 minutes after the vibration, the apparent volume of the sediment is read on the scale of a measuring cylinder and is defined as the degree of sedimentation.

A second aspect of the present invention is a method for producing a surface-treated calcium carbonate powder having such specific physical properties, and a third aspect of the present invention is a surface-treated calcium carbonate powder having such specific physical properties. Each of the contents includes a moisture-curable one-pack type resin composition containing a body.

The degree of sedimentation in the present invention is an index of the difficulty of adaptation of the surface-treated calcium carbonate powder to water. In other words, the surface of the calcium carbonate powder having a predetermined weight becomes hydrophobic. It is an index of the ratio of what is being read. That is, in the one-pack type resin composition,
It is thought that the more hydrophobic the surface of the calcium carbonate compounded by the surface treatment agent, the more the exposure of calcium ions is reduced and the amount of water adsorbed on the calcium carbonate surface is reduced, and the physical properties are reduced by the adsorbed water. Storage stability, foaming, etc. are improved. In addition, when the calcium carbonate is heated to remove the adsorbed water before being mixed with the one-pack resin, the more the surface of the compounded calcium carbonate is hydrophobized, the more easily the water can be removed, and the above physical properties are improved. Is done. Therefore, in preparing the one-pack type resin composition, it is most important to regulate the surface hydrophobicity of the calcium carbonate used in order to improve the storage stability and suppress the occurrence of foaming and cracks. As a method of defining the degree of surface hydrophobicity, the measurement of the degree of sedimentation is effective.

If the degree of sedimentation exceeds 10 ml, the surface is not sufficiently hydrophobized, so that the storage stability is poor and foaming, cracks, etc. are liable to occur. Therefore, the degree of sedimentation should be less than 10 ml, preferably less than 5 ml, more preferably 0 ml, ie free of sediment.

The degree of sedimentation of the surface-treated calcium carbonate powder is 1
The method of setting the volume to 0 ml or less is not particularly specified,
It is promising to select fatty acid esters as surface treatment agents. The fatty acid ester is not particularly limited, but the fatty acid constituting the fatty acid ester is preferably a higher fatty acid having as many carbon atoms as possible, in addition to storage stability, in addition to high thixotropy,
It can be expected to have slump resistance. Specifically, the carbon number is preferably 8 or more. The ester group, which is the other component, is not particularly limited as in the case of the fatty acid portion, but the greater the carbon number, the more advantageous the thixotropic property and the slump resistance. Such fatty acid esters include, for example, stearic acid stearate, stearic acid laurate, palmitic acid stearate, palmitic acid laurate and the like. Similar effects can be expected not only with esters formed from monohydric alcohols, but also with fatty acid esters formed from polyhydric alcohols such as glycerin. These are used alone or in combination of two or more.

However, there is a case where a desired degree of sedimentation cannot be obtained simply by adding and mixing a fatty acid ester to calcium carbonate. Preferably, one or more of the following three methods are used in combination. good.

First, as a first method, after calcium carbonate is surface-treated with a surface treatment agent, the calcium carbonate is treated at a temperature equal to or higher than the melting point of the surface treatment agent for 1 hour to 240 hours, preferably 6 hours to 120 hours. Is to hold.
By this holding, uniform and sufficient adsorption of the treatment agent is performed. If the holding time is less than 1 hour, the treatment agent may not be sufficiently adsorbed, and the storage stability of the one-pack type resin composition may be disadvantageous. When the holding time is 240 hours or longer, hydrolysis of the surface treating agent described later proceeds, which also causes deterioration of storage stability.

As a second method, when performing surface treatment on calcium carbonate, a sufficient stirring treatment is performed at a temperature at the time of surface treatment that is equal to or higher than the melting point of the surface treatment agent. If the surface treatment temperature is lower than the melting point of the surface treatment agent, the surface treatment agent is often not adsorbed on the surface of the individual calcium carbonate particles, no matter how vigorous stirring, so that both remain in a mixed state. Even if the surface treatment agent is melted by applying heat above the melting point to the body, it cannot be uniformly adsorbed to the whole system, and the storage stability of the one-pack type resin composition may be inconvenient. The surface treatment time is usually about 30 minutes to 1 hour.

Further, as a third method, when performing surface treatment on calcium carbonate, an aqueous suspension of calcium carbonate is prepared, and the viscosity of the suspension during the surface treatment (B-type viscometer, 6
0 rpm) is set to 1000 cp or more. As a result, the surface treatment agent is uniformly dispersed in the system, and the chance of contact with the individual particles of calcium carbonate is increased, and the adsorption on the surface becomes more uniform. If the viscosity of the suspension is less than 1000 cp, the surface treating agent and calcium carbonate may be separated, and eventually the adsorption of the treating agent becomes non-uniform, which is also the storage stability of the one-pack type resin composition. May be inconvenient.

Further, when using fatty acid esters as the surface treating agent, it should be noted that these esters may be deteriorated by hydrolysis.
When the surface treatment agent undergoes hydrolysis, it becomes an acid component and an alcohol, so that the storage stability decreases. For this reason, the surface treatment agent should be operated so as not to hydrolyze as much as possible.
When the ratio of the fatty acid ester to the entire surface treatment agent is less than 70% by weight, the storage stability becomes extremely poor.

The surface-treated calcium carbonate can be dried and crushed by a usual operation to obtain a surface-treated calcium carbonate powder.

The calcium carbonate used in the present invention is not particularly limited, and may be selected according to the physical properties of the desired one-pack type resin composition. Calcium and limestone are calcined once to form quicklime, which is produced by passing carbon dioxide gas through an aqueous suspension of slaked lime prepared by hydration. Various methods such as solution-processed calcium carbonate can be selected depending on the purpose. However, in order to obtain high thixotropy and good slump resistance, it is preferable to use a BET specific surface area of 8
Calcium carbonate of at least m ² / g, more preferably at least 15 m ² / g is used. More preferably, a higher BE
Precipitated calcium carbonate which can provide a T specific surface area is more preferable. Even for heavy calcium carbonate or precipitated calcium carbonate, if the BET specific surface area is less than 8 m ² / g, it is not preferable because it is difficult to impart high viscosity.

The one-pack type resin to which the surface-treated calcium carbonate of the present invention is blended is not particularly limited, and examples thereof include polyurethane, polysulfide, silicone, and modified silicone. These may be used alone or in combination of two or more. Is also good. In addition, applications are sealing materials, adhesives,
Examples include flooring materials and paints. The number of parts of the calcium carbonate of the present invention to be added to the one-pack type resin may vary depending on the type and use of the resin.
The amount is preferably 20 to 150 parts by weight, more preferably about 40 to 100 parts by weight, based on 0 parts by weight. If the amount is less than 20 parts by weight, the desired effect of the present invention is not sufficient.
If it exceeds 50 parts by weight, the viscosity may be too high and the workability may be deteriorated.

As for the storage stability, since moisture is greatly involved, drying before use makes it even more reliable. As the drying condition, for example, it may be left in an oven at about 100 ° C. for several hours. For the composition of the present invention, in addition to the above, in order to adjust the viscosity, other physical properties,
Fillers such as colloidal silica, talc, kaolin, zeolite, resin balloons, glass balloons, plasticizers such as dioctyl phthalate and dibutyl phthalate, toluene,
Aromatic hydrocarbons such as xylene, aliphatic hydrocarbons such as hexane and butane, petroleum solvents such as gasoline, ketones such as acetone and methyl ethyl ketone, solvents exemplified by ether esters such as cellosolve acetate, silicone oil, fatty acids One or more additives such as an ester-modified silicone oil and various other additives and coloring agents can be added as necessary.

[0022]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited by these. The measurement or evaluation other than the degree of sedimentation was performed by preparing a polyurethane one-pack type sealing material by the following test method.

[Test Method] [Blending] Resin (Takenate L1004, manufactured by Takeda Pharmaceutical Co., Ltd.) 150 parts by weight Sample Surface-treated calcium carbonate 100 parts by weight [Kneading method] The above compound was kneaded with a small kneader to obtain a sealing material. Created. [Viscosity measuring method] A B8U type viscometer was used.
7). [Water content measurement method] After drying at 105 ° C for 2 hours, the content was measured with a Karl Fischer moisture meter. [Storage stability test method] It was left in an oven at 50 ° C for 4 weeks. [Slump resistance] The state of vertical construction was visually determined. ：: Good slump resistance. X: Poor slump resistance. [Crack] The state of the surface after curing of the sealant was visually determined. ：: There is a crack. ×: No crack.

Example 1 A BET specific surface area of 30 m ² / g and a slurry viscosity of 2000 were adjusted to a concentration of 160 g CaCO ₃ / liter and a temperature of 60 ° C.
80 g of stearyl glycerin ester was added to 10 liters of an aqueous slurry of precipitated calcium carbonate made of cp, and the mixture was vigorously stirred for 1 hour to perform surface treatment. After the surface treatment, this calcium carbonate slurry was kept still at 60 ° C. or higher for 6 hours, then dehydrated, dried and pulverized to obtain a surface-treated calcium carbonate powder having a sedimentation degree of 0 ml. Add this powder for another 110
After drying at 2 ° C. for 2 hours, a one-pack polyurethane sealing material was prepared according to the above-mentioned test method, and its effect was tested. The results are shown in Tables 1 and 3.

Example 2 In Example 1, the surface treatment agent stearyl glycerin ester was changed to stearyl stearate, and the treatment temperature was changed to 60 ° C.
Except that the temperature was changed to 2 ° C., all were the same as Example 1. The obtained surface-treated calcium carbonate powder had a sedimentation degree of 0 ml. After further drying this powder at 110 ° C. for 2 hours,
A one-pack polyurethane sealant was prepared according to the test method described above, and its effect was tested. The results are shown in Tables 1 and 3.

Example 3 The procedure was the same as Example 1 except that the slurry viscosity was changed from 2000 cp to 1500 cp and the retention time after surface treatment was changed to 168 hours. The obtained surface-treated calcium carbonate powder had a sedimentation degree of 0 ml. After the powder was further dried at 110 ° C. for 2 hours,
A liquid polyurethane sealant was made and tested for its effectiveness. The results are shown in Tables 1 and 3.

[0027]

[Table 1]

Comparative Example 1 In Example 1, except that the slurry viscosity was changed from 2000 cp to 100 cp, the surface treatment agent stearyl glycerin ester to stearyl stearate, the treatment temperature from 60 ° C. to 62 ° C., and the holding time from 6 hours to 0 hours. All were the same as in Example 1. The obtained surface-treated calcium carbonate powder has a sedimentation degree of 11
ml. After the powder was further dried at 110 ° C. for 2 hours, a one-pack polyurethane sealing material was prepared by the above-described test method, and the effect was tested. The results are shown in Tables 2 and 3.

Comparative Example 2 Example 1 was the same as Example 1 except that the slurry viscosity was changed from 2000 cp to 100 cp and the holding time from 6 hours to 0 hours. The obtained surface-treated calcium carbonate powder had a degree of sedimentation of 11 ml. After the powder was further dried at 110 ° C. for 2 hours, a one-pack polyurethane sealing material was prepared by the above-described test method, and the effect was tested. The results are shown in Tables 2 and 3.

Comparative Example 3 Example 1 was repeated except that the slurry temperature was changed from 60 ° C. to 50 ° C. and the surface treatment was performed at 50 ° C. for 1 hour.
The same as above. The resulting surface-treated calcium carbonate powder had a degree of sedimentation of 18 ml. This powder is further heated at 110 ° C. for 2 hours.
After drying for one hour, a one-pack polyurethane sealing material was prepared according to the above-described test method, and its effect was tested. The results are shown in Tables 2 and 3.

Comparative Example 4 In Example 1, the surface treatment agent stearyl glycerin ester was replaced with stearyl stearate, and the treatment temperature of 60 ° C. was changed to 62 ° C.
Then, the procedure was the same as in Example 1 except that the holding time after the surface treatment was changed from 6 hours to 300 hours. The obtained surface-treated calcium carbonate powder had a sedimentation degree of 17 ml. After the powder was further dried at 110 ° C. for 2 hours, a one-pack polyurethane sealing material was prepared by the above-described test method, and the effect was tested. The results are shown in Tables 2 and 3.

Comparative Example 5 In Example 1, the surface treatment agent stearyl glycerin ester was used as sodium abietic acid, and the slurry viscosity was set at 2,000 cp.
It was the same as Example 1 except that it was changed to 00cp. The resulting surface-treated calcium carbonate powder had a degree of sedimentation of 15 ml. After further drying this powder at 110 ° C. for 2 hours,
A one-pack polyurethane sealant was prepared according to the test method described above, and its effect was tested. The results are shown in Tables 2 and 3.

Comparative Example 6 In Example 1, 40 g of stearyl glycerin ester and 4 g of
All the procedures were the same as in Example 1, except that the surface treatment was carried out using 0 g of sodium abietic acid. The obtained surface-treated calcium carbonate powder had a sedimentation degree of 14 ml. After the powder was further dried at 110 ° C. for 2 hours, a one-pack polyurethane sealing material was prepared by the above-described test method, and the effect was tested. The results are shown in Tables 2 and 3.

[0034]

[Table 2]

[0035]

[Table 3]

[0036]

As described above, the surface-treated calcium carbonate powder of the present invention is particularly useful for a moisture-curable one-pack type resin composition, and has excellent storage stability, workability, slump resistance, and excellent moisture in cracks. A cured one-pack type resin composition can be provided.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08L 83/04 C08L 83/04

Claims (7)

[Claims] 1. A surface-treated calcium carbonate powder having a degree of sedimentation of 10 ml or less according to the following measuring method. [Sedimentation degree] 70 ml of water at 25 ° C was placed in a 100 ml stoppered measuring cylinder.
And add 7 g of sample calcium carbonate powder. Using a shaker with an amplitude of 4 cm and 320 cycles / min, the resulting mixture is shaken for 15 minutes. After settling for 10 minutes after the vibration, the apparent volume of the sediment is read on the scale of a measuring cylinder and is defined as the degree of sedimentation. 2. The surface-treated calcium carbonate powder according to claim 1, wherein the surface-treating agent contains at least 70% by weight of a fatty acid ester in the entire surface-treating agent. 3. The calcium carbonate has a BET specific surface area of 8 m ^2.
The surface-treated calcium carbonate powder according to claim 1 or 2 or more. 4. After the surface treatment of calcium carbonate with a surface treatment agent, the treatment is carried out for 1 hour or more at a temperature not lower than the melting point of the surface treatment agent.
A method for producing a surface-treated calcium carbonate powder, wherein the powder is held for 40 hours or less. 5. The production method according to claim 4, wherein the surface treatment is carried out by stirring at a temperature higher than the melting point of the surface treatment agent. 6. The process according to claim 4, wherein an aqueous suspension of calcium carbonate is prepared and the suspension is subjected to a surface treatment at a viscosity (B-type viscometer, 60 rpm) of 1000 cp or more. 7. A moisture-cured one-pack type resin composition comprising the surface-treated calcium carbonate powder according to claim 1.