JPS5833270B2 - Netsuyouyukeiromenhifukuyotoriyososeibutsu - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hot-melt road coating coating composition with improved coating film flexibility, compressive strength, and fluidity during application.

Heat-melting road surface coating paints have been used in recent years due to the increase in traffic volume and the development of road networks, as they can be easily and quickly worked without stopping vehicle traffic, and because of the pollution control aspect of removing solvents. The amount has increased significantly.

Furthermore, more recently, so-called surface paving has begun, in which road divisions are not only marked with lines, but also divided by color by painting.

Accordingly, requirements for the workability and durability of road surface coating paints are becoming even more severe.

At first glance, the binder used in hot-melt road coating paints may seem to have the same composition as hot-melt adhesives, but road coating paints generally contain 50% Filler is added at a higher concentration than the weight of the rice cake.

When such a high concentration of filler is added to a typical hot melt adhesive, the melt viscosity increases significantly, making the application process extremely difficult.

Therefore, until now, maleated rosin has been used exclusively as a caking agent for hot-melt road coating paints.

However, since maleated rosin is made from a natural product called rosin, it is expensive and has a problem of being unable to meet the increasing demand due to its limited supply.

Therefore, the present applicant discovered that malein could be substituted for rosin by carboxyl-modified hydrocarbon resin or its esterified modified product, and proposed it earlier (Japanese Unexamined Patent Publication No. 49/1989).
-17824).

However, although paints using this carboxyl-modified hydrocarbon as a binder had improved fluidity, they were unsatisfactory in terms of low-temperature flexibility, quick drying, and stain resistance.

Therefore, the present inventors further investigated ways to improve the above-mentioned coating material, and as a result, they discovered the composition of the present invention.

An object of the present invention is to provide a hot-melt road surface coating coating composition that has excellent flexibility, especially flexibility at low temperatures, high compressive strength, and excellent fluidity during application.

Another object of the present invention is to provide an excellent hot-melt road coating coating composition that is inexpensive, has a good hue, takes a short drying time, and has good stain resistance.

That is, the present invention comprises (a) 2 to 20 parts by weight of either ethylene-vinyl acetate copolymer or active polypropylene, (b) a carboxyl-modified hydrocarbon resin having an acid value of 0.1 to 25, or the modified 60 to 96 parts by weight of an ester-modified hydrocarbon resin obtained by reacting a resin and an alcohol, (c) 2 to 20 parts by weight of low molecular weight polyethylene with a number average molecular weight of 400 to 3,000 or its carboxyl modified product, (d) Inorganic This is a hot-melt type road surface coating coating composition comprising 200 to 700 parts by weight of fillers and pigments, and optionally a plasticizer and glass beads.

As a raw material for the modified hydrocarbon resin used as the main component of the binder in the coating composition of the present invention, any fraction with a boiling point of -10 to 280°C under normal pressure produced by thermal decomposition of petroleum can be used as a raw material. Resins obtained by polymerization using Krafuch's catalyst, and pure monomers that can be cationically polymerized with the above fractions in amounts of up to 50% by weight, such as unsaturated aliphatic compounds such as isobutylene, butadiene, isoprene, piperylene, and dicyclopentadiene. A resin obtained by copolymerizing unsaturated alicyclic compounds such as or unsaturated aromatic compounds such as styrene, vinyltoluene, isopropenyltoluene, α-methylstyrene, and indene by a similar method,
Alternatively, it includes resins obtained by cationic polymerization or radical polymerization of only the above-mentioned unsaturated aromatic compounds, as well as resins obtained by hydrogenating these resins.

Among these, so-called aliphatic petroleum resins, which are produced by polymerizing fractions with boiling points of 110°C to 60°C under normal pressure produced by thermal decomposition of petroleum using a Friedel-Crauch catalyst, are easy to modify. Moreover, it is preferable because the modified product has excellent heat resistance and hue.

The hydrocarbon resin obtained by the above method is solid at room temperature, has a number average molecular weight of 500 to 3000, preferably 700 to 2000, and has a softening point (ring and ball method) of 60 to 150°C, preferably 70 to 1
The temperature is 20℃, and the hue (Gardner, resin 100 lines) is 1.
It is 0 or less, preferably 8 or less.

If these hydrocarbon resins are mixed with a large amount of filler as in the composition of the present invention, they have extremely poor fluidity when melted and lack paintability, so they are modified and modified.

The modified hydrocarbon resin used in the present invention is obtained by introducing a carboxyl group into a hydrocarbon resin.

As a method of introducing a carboxyl group, a method of oxidizing a hydrocarbon resin or a method of grafting an unsaturated carboxylic acid can be adopted.

Oxidation of hydrocarbon resin can be carried out, for example, while stirring the molten resin.
This can be carried out by blowing in an oxygen-containing gas such as oxygen or air.

In this case, it is possible to shorten the reaction time by using a radical initiator, or it is not necessary to use a radical initiator.

A method of grafting an unsaturated carboxylic acid onto a hydrocarbon resin includes heating the hydrocarbon resin and the unsaturated carboxylic acid to high temperatures, for example, in the presence or absence of a solvent, with or without the addition of a radical initiator. It is carried out by

Examples of the unsaturated carboxylic acid grafted to the hydrocarbon resin include acrylic acid, methacrylic acid, fumaric acid, maleic acid, itaconic acid, citraconic acid, maleic anhydride, citraconic anhydride, itaconic anhydride, and the like. .

Among these, maleic anhydride is preferred.

The modified hydrocarbon resin thus obtained has an acid value of 0.
It needs to be in the range of 1 to 25, preferably 1 to 20.

If the acid value is less than 0.1, the fluidity of the composition during melting will be poor, and if it is more than 25, the hue of the modified hydrocarbon resin will deteriorate, which is not preferable.

Note that it is also effective to react the carboxyl group-containing modified hydrocarbon resin obtained by the above method with an alcohol to introduce an ester bond.

In this case, thermal stability at high temperatures is improved. Alcohols include methanol, ethanol, propatool,
Polyhydric alcohols such as butanol, octatool, glycidyl alcohol, alkylene glycol monoalkyl ether nato, ethylene glycol, diethylene glycol, propylene glycol, butanediol, and glycerin can be used. It can be obtained by heating both at a temperature of 250°C to 250°C.

In the coating composition of the present invention, ethylene-vinyl acetate copolymer (hereinafter abbreviated as EVA) or atactic polypropylene is added to 100 parts by weight of the coating binder in order to improve the flexibility of the coating, especially low-temperature flexibility. Add 20 parts by weight.

The EVA useful in the present invention is a mixture of ethylene and vinyl acetate.
A copolymer obtained by radical polymerization at a high pressure of 00 to 3000 atm, with a mole φ of vinyl acetate of 10 to 36
, especially those with numbers 19 to 28 are preferably used.

EVA flow index (190℃, ASTM D-1238)
or 1 to 40.0. Preferably, those in the range of 20 to 400 are used.

If the flow index is less than 1, the viscosity of the composition will increase, which is undesirable, and if it is thicker than 400, the flexibility improvement effect will be poor.

In the present invention, active polypropylene can be used for the same purpose as EVA.

The active polypropylene useful in the present invention refers to a boiling n-heptane soluble resin which is produced as a by-product during the synthesis of crystalline polypropylene and has a number average molecular weight of 2,000 to 40,000, preferably 3,000 to 20,000.

If the number average molecular weight is less than 2,000, the flexibility improvement effect is poor, and if it is more than 40,000, the viscosity of the composition increases.

Maleated rosin, which has been used as a binder for road surface coating paints, has poor compatibility with atactic polypropylene, so the improvement effect of atactic polypropylene could not be expected, or the modified hydrocarbon used in the present invention Since the resin has extremely good compatibility with atactic polypropylene, the above-mentioned effects can be obtained.

In the composition of the invention, EVA or active polypropylene is added to 100 parts by weight of the paint binder, and 2 to 20 parts by weight of
1, preferably in the range of 3 to 12 parts by weight.

If it is less than 2 parts by weight, the desired effect will not be obtained, and if it is more than 20 parts by weight, the melt viscosity of the composition will be too high, making it difficult to apply the coating.

Also, the stain resistance of the paint is reduced. In the composition of the present invention, low molecular weight polyethylene or its carboxyl modified product is blended in order to reduce the melt viscosity of the composition, shorten the drying time, and improve stain resistance and high temperature properties.

The low molecular weight polyethylene or its carboxyl modified product used in the composition of the present invention refers to a homopolymer of ethylene, or other olefin containing 20 moles or less of ethylene and propylene, 1-butene, 1-hexene, 1-heptene, etc. or a thermal decomposition product of these polymers with a number average molecular weight of 400 to 3000, preferably 60.
0 to 1500, or those further modified by oxidation or unsaturated carboxylic acid.

If the number average molecular weight of the low molecular weight polyethylene is 100 or less, the effect of improving high temperature properties and stain resistance cannot be obtained;
If it is more than 00, it cannot be used because of poor compatibility with the modified hydrocarbon resin and small viscosity-lowering effect.

Waxes obtained from petroleum residues, such as paraffin wax and microcrystalline wax, cannot be used in the present invention because they do not have high-temperature properties, improve stain resistance, or shorten drying time.

The carboxy-modified product of low-molecular-weight polyethylene used in the present invention can be obtained by oxidizing low-molecular-weight polyethylene or grafting an unsaturated carboxylic acid. For example, it is preferable to melt low molecular weight polyethylene and blow oxygen or an oxygen-containing gas into it, but it is also preferable to contact it with oxygen-containing air in the form of powder or fibers, or to suspend it in an aqueous medium. This can also be done by oxidation or other methods.

The acid value of the oxidation-modified polyethylene wax obtained by the above method is usually 30 or less, particularly preferably 0.5 to 20. If it is 30 or more, the thermal stability of the composition will be impaired and a paint with a good hue may not be obtained. I can't get it.

The unsaturated carboxylic acid graft modified wax is obtained by grafting an unsaturated carboxylic acid or a derivative of an unsaturated carboxylic acid onto the above-mentioned low molecular weight polyethylene using a radical initiator in the presence or absence of a solvent at a reaction temperature higher than its decomposition temperature. Any known method for adding the cursor may be used.

Suitable solvents include halogenated hydrocarbons, benzene, alkylbenzenes, and linear saturated aliphatic hydrocarbons.

Unsaturated carboxylic acids and their derivatives include acrylic acid, methacrylic acid, fumaric acid, maleic acid, itaconic acid, citraconic acid, maleic anhydride, citraconic anhydride,
Among these, maleic anhydride is most suitable.

As the radical initiator, acyl peroxides, ber esters, and dialkyl peroxides are suitable, and among them, dialkyl peroxides are most suitable.

Benzoyl peroxide, t-butyl peroxybenzoate, t-butylcumyl peroxide, di-t-butyl peroxide, dicumyl peroxide, α, α/(1
butylperoxy)1,4-diisopropylbenzene,
2,5-dimethyl-2,5s)(t--f thylperoxy)hexyne-3,2,5-dimethyl-2,5-di(t
-butylperoxy)hexane can be exemplified.

The use of a solvent is appropriate for the purpose of reducing the viscosity of low molecular weight polyethylene and purifying the reactant following the reaction, but in particular, in order to obtain the unsaturated carboxylic acid-modified low molecular weight ethylene of the purpose of the present invention, a solvent is used. It is not necessary to use

Unsaturated carboxylic acids or derivatives thereof are used alone or in combination of two or more, and the amount used is controlled depending on the degree of modification of the modified product or the presence or absence of a solvent, but it is usually 0.00 parts by weight per 100 parts by weight of low molecular weight polyethylene. 1 to 30 parts by weight are used.

The radical initiator is usually used in an amount of 0.03 to 20 mmol per 100 parts by weight of low molecular weight polyethylene.

The reaction temperature is usually 100 to 300°C, but 120°C
Preferably, the temperature is between 200°C and 200°C.

The reaction temperature is usually 1 minute to 5 hours, and the higher the reaction temperature, the shorter the reaction time.

However, the higher the reaction temperature and the higher the degree of modification, the worse the hue becomes, so the reaction humidity should be determined in consideration of these factors.

Although the unsaturated carboxylic acid or its derivative and the radical initiator may be added all at once at the beginning of the reaction, it is preferable to continuously supply both to the reaction system at a rate depending on the graft addition rate of the reaction system.

The reaction format may be batchwise or continuous.

The reaction product may be used after being purified by removing the reaction solvent, monomer and initiator.

The resulting unsaturated carboxylic acid-modified wax usually contains 0.1 to 10 wt% of monomer units, preferably 0.1 to 6 wt%.

In addition, ester bonds may be introduced into the oxidized or unsaturated carboxylic acid-modified polyethylene wax by the same purpose and means as those for introducing ester bonds by reacting the carboxyl-modified hydrocarbon resin with an alcohol.

In the present invention, when the low molecular weight polyethylene is carboxyl-modified to the above degree, the compatibility with the carboxyl-modified hydrocarbon resin and the affinity with inorganic fillers and pigments are improved, so that the melt viscosity of the composition is further reduced. Although this is preferred from the viewpoint of the surface gloss of the coating film, the object of the present invention can be achieved to some extent even if it is not modified.

The amount of low molecular weight polyethylene or its carboxyl modified product in the coating composition of the present invention must be in the range of 2 to 20 parts by weight, preferably 4 to 12 parts by weight, based on 100 parts by weight of the coating binder.

If it is less than 2 parts by weight, the blending effect will be poor, and if it is blended in more than 20 parts by weight, problems such as a decrease in the flexibility, compressive strength, and adhesiveness of the paint will occur.

The low molecular weight polyethylene used in the present invention exhibits the desired effect in the highly filler-containing coating composition of the present invention only when combined with a modified hydrocarbon resin.

That is, in road surface coating paints containing maleated rosin as a main component, low molecular weight polyethylene and maleated rosin cannot be used because they have extremely poor compatibility.

Furthermore, as mentioned above, road surface coating paints that are mainly composed of unmodified hydrocarbon resins have extremely poor fluidity, or even if low molecular weight polyethylene is blended with them, the fluidity of the paints within the blending range of the present invention is extremely low. When blended in a large amount, the fluidity is improved, but on the other hand, the compressive strength, adhesion, and flexibility of the coating film are extremely reduced, so that it cannot be used practically.

As described above, the binder of the hot-melt road coating composition of the present invention is composed of EVA or active polypropylene, a modified hydrocarbon resin, low molecular weight polyethylene or a carboxyl modified product thereof, and further includes, for example, vegetable oil, mineral oil,
It may also contain small amounts of plasticizers such as polybutene, liquid paraffin, and DOP, heat stabilizers, weather stabilizers, and the like.

One of the characteristics of the road surface coating paint composition of the present invention is that 200 to 700 parts by weight of an inorganic filler and pigment are blended with 100 parts by weight of a binder.

Fillers are used primarily to improve the compressive strength, stain resistance, and drying properties of paints, as well as to reduce cost.

Therefore, whether or not it is possible to incorporate a large amount of filler without impairing other properties is an issue that cannot be overlooked for road coating paints.

Examples of fillers used in the present invention include calcium carbonate, silica sand, talc, and calcium sulfate.

As the pigment for coloring the paint, any pigment used in ordinary paints, such as titanium white, red iron, zinc white, yellow lead, phthalocyanine blue, carbon black, etc., can be used.

These fillers and pigments are used in an amount of 2 parts by weight per 100 parts by weight of the binder.
00 to 700 parts by weight, preferably 400 to 60 parts by weight
It is blended in a range of 0 parts by weight.

If it is less than 200 parts by weight, the compressive strength and stain resistance of the coating material will decrease, and if it is more than 700 parts by weight, the melt viscosity will increase and the coating film will become brittle.

The composition of the present invention may further contain known glass beads and the like to impart light reflectivity.

Sprinkling cut glass powder on the surface of the paint is extremely effective in preventing the paint from slipping.

The method for preparing the road coating paint composition of the present invention includes:
Examples include a method in which each portion of the binder is melted and then blended with fillers and pigments while stirring, and a method in which all components are mixed and then dissolved.

Furthermore, the paint of the present invention can be easily applied using a conventional hot-melting road surface coating application machine.

As described above, the hot-melt road coating paint composition of the present invention has good fluidity during application, excellent flexibility at low humidity, compressive strength, stain resistance, and high-temperature properties, and is quick-drying. It simultaneously satisfies most of the performance requirements for road surface coatings, such as good color and color, and is cheaper and has better performance than the maleated rosin paints that have been used in the past. It has many advantages such as:

In addition, the number average molecular weight as used in the present invention refers to a value determined by a boiling point elevation method using a sample as a toluene solution.

Next, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited to these examples unless it exceeds the gist thereof.

Example 1 Aliphatic hydrocarbon resin (trade name Hiretsu P-100L1
Manufactured by Mitsui Petrochemical Industries, softening point 97°C, number average molecular weight 16
20) was melted at 210°C, maleic anhydride was added under stirring, and the mixture was reacted for 1 hour to obtain a maleic acid graft-modified hydrocarbon resin having a softening point of 98°C and an acid value of 4.8.

100 parts by weight of this resin and EVA (product name Evaflex 2201 manufactured by Mitsui Polychemicals, melt index 1)
Oxidation-modified low-molecular-weight polyethylene obtained by melting low-molecular-weight polyethylene at 150°C and oxidatively modifying it by blowing air (number average molecular weight 1400, acid value 1.2) 6 Parts by weight, 75 parts by weight of titanium white (anatase type), 450 parts by weight of calcium carbonate, and 10 parts by weight of naphthenic mineral oil were placed in a heating stirrer and melted and mixed at 200'C for 2 hours to obtain the desired paint.

Example 2 Aliphatic hydrocarbon resin (trade name Hiretsu P-100L1
(manufactured by Mitsui Petrochemical Industries) was melted at 180°C and oxidized for 1 hour by blowing air under stirring to obtain a softening point of 99°C and oxidation of 0.
Oxidation-modified hydrocarbon resin No. 2 was obtained.

A paint was prepared in the same manner as in Example 1 except that this resin was used as a modified hydrocarbon resin.

Example 3 The maleic acid graft-modified hydrocarbon resin obtained by the method of Example 1 was reacted with n-butanol at 180°C for 2 hours in a closed container, resulting in a softening point of 98°C, an acid value of 1.5, and a saponification value of 8. .0
A modified hydrocarbon resin having ester bonds was obtained.

The same procedure as in Example 1 was carried out except that 100 parts by weight of this resin was used.

Example 4 Instead of EVA, active polypropylene (number average molecular weight 5300, density 0.86 g/cIfL1 softening point 1
The same procedure as in Example 1 was carried out except that 8 parts by weight (03°C) was used.

Example 5 Low molecular weight polyethylene (number average molecular weight 700
The same procedure as in Example 1 was carried out except that the amount of 1 oxide was changed to 0)6 parts by weight.

Example 6 Maleic acid graft modified hydrocarbon resin 100 of Example 1
Parts by weight, EVA (trade name Evaflex 410, manufactured by Mitsui Polychemicals, melt index 400, vinyl acetate content 19 mol) 8 parts by weight, oxidation-modified low molecular weight polyethylene (number average molecular weight 1400, acid value 1.2) 6 parts by weight Department,
The same procedure as in Example 1 was conducted except that 75 parts by weight of titanium white (anatase type), 525 parts by weight of calcium carbonate, and 10 parts by weight of naphthenic mineral oil were used.

Example 7 100 parts by weight of low molecular weight polyethylene was chopped and mixed with 2.5 parts by weight of maleic anhydride and 0.4 parts by weight of di-t-butyl peroxide as an initiator at 160° C. under nitrogen atmosphere while stirring. It takes an hour to drip,
The reaction was further carried out after 2 hours to obtain maleic acid-modified low molecular weight polyethylene (number average molecular weight: 1200, acid value: 22).

A sample was prepared using the same formulation as in Example 1 except that this maleic acid-modified low-molecular-weight polyethylene was used in place of the oxidation-modified low-molecular-weight polyethylene of Example 1.

The performance evaluation results of the coating compositions obtained by the above method are shown in Table 1.

In the performance evaluation, the softening point and compressive strength were tested according to the method of JIS-5665 (welding type traffic paint).

The curing and drying time was measured by the method of JIS-5400.

Adhesion was determined by scratching the coating film applied to the steel plate with a razor.
The state of peeling of the coating film was observed and evaluated on the following four levels.

◎・・・・・・Not peeled off at all, ○・・・・・・Peeled off a little, △・・・・・・Peeled off quite a bit, ×・・・・・・
- Peel off before making any scratches.

Flexibility is similarly achieved by applying a falling weight (2
01) was dropped and the state of cracks or peeling of the coating film was observed and evaluated on the following four scales.

◎・・・・・・No cracks or peeling occurs, ○・・・
・・・・Some cracks or peeling occur, △・・・・
...Cracks and peeling occur, ×...The paint film scatters.

The stain resistance was measured after spraying a powder consisting of 95 parts by weight of red clay and 5 parts by weight of carbon black on the paint film 24 hours after application.
By removing the powder with a brush and comparing the contamination status of the coating film with the sample, the results were ◎ and ○.

Evaluation was made on a four-level scale of △ and ×, and 0 or more was considered to be a pass.

Comparative Example 1 A mixture having the same composition as in Example 5 except for using an unmodified aliphatic hydrocarbon resin (trade name Hiretsu p-100L, manufactured by Mitsui Petrochemical Industries) was placed in a heating stirring device and heated for 22 hours.
Although melt mixing was attempted at 0° C., the melt viscosity increased significantly and it was not possible to obtain the desired paint that could be stirred.

Comparative Example 2 A paint was obtained in the same manner as in Example 1, except that EVA and low molecular weight polyethylene were not mixed.

The results are shown in Table 2, and it is clear that if EVA and low molecular weight polyethylene are not blended, the compressive strength at low temperatures will be greatly reduced, as well as the softening point, drying time, and stain resistance will be reduced.

Comparative Example 3 The same procedure as in Example 1 was carried out except that low molecular weight polyethylene was not blended and naphthenic mineral oil was increased to 16 parts by weight instead.

Comparative Example 4 The same procedure as in Example 4 was carried out except that low molecular weight polyethylene was not blended and naphthenic mineral oil was increased to 16 parts by weight instead.

The results of Comparative Examples 3 and 4 are shown in Table 2. If naphthenic mineral oil, which is a plasticizer, is used instead of low molecular weight polyethylene, the softening point and stain resistance will decrease, and the drying time will become longer. I understand.

Comparative Example 5 When 35 parts by weight of low molecular weight polyethylene was added to the composition of Example 4, as seen in the results shown in Table 2, compressive strength, flexibility, and adhesiveness were significantly impaired.

Example 6 The composition of Example 4 was used to produce 35% of the active polypropylene.
A paint was obtained in the same manner as in Example 4 except that the parts by weight were changed.

As shown in Table 2, this material has an extremely high melt viscosity and is difficult to apply.

Example 7 The same procedure as in Example 1 was carried out except that EVA was not blended.

From the results shown in Table 2, it is clear that compressive strength and flexibility at low temperatures cannot be obtained unless EVA or active polypropylene is blended.

Example 8 The performance of paints prepared using maleated rosin is also listed in Table 2.

Claims (1)

[Claims] 1(a) 2 to 20 of any one of ethylene-vinyl acetate copolymer or atactic polypropylene
parts by weight, (b) a carboxyl-modified hydrocarbon resin having an acetic acid value of 0.1 to 25 or an ester-modified hydrocarbon resin obtained by reacting the modified resin with alcohol 6
0 to 96 parts by weight, (c) low molecular weight polyethylene with a number average molecular weight of 400 to 3000 or its carboxyl modified product 2 to 2
(d) 200 to 700 parts by weight of an inorganic filler and a pigment, and optionally a plasticizer and glass beads.