JPS5887118A - Asphalt composition - Google Patents

Abstract

PURPOSE:An asphalt composition having good shapability and a well-controllable curing rate, prepared by mixing asphalt with a polydiene chain-containing polyisocyanate and a cure accelerator. CONSTITUTION:Use is made of a urethane prepolymer having an isocyanato group on a molecular end (e.g., polyoxypropylene glycol/tolylene diisocyanate prepolymer, of which the isocyanato groups may be blocked ) obtained by reacting an organic polyisocyanate with an active hydrogen-containing compound under a condition including an NCO/OH (eq. ratio) >= about 1.5. Namely, there are mixed together (A) 100pts.wt. asphalt (e.g., straight asphalt), (B) 3-300pts.wt. above polydiene chain-containing polyisocyanate and (C) 0.05-5pts.wt., per 100pts.wt. component B, cure accelerator (e.g., sodium dibutyldithiocarbamate).

Description

[Detailed description of the invention] The present invention relates to asphalt compositions.

Modified asphalt, which is a mixture of asphalt with thermoplastic rubber and powdered vulcanized rubber, is well known and is used in waterproof sheets and the like.

However, although these modified asphalts have excellent moldability, they have the disadvantage that the product is highly temperature dependent and flows at high temperatures.

To solve this problem, we have developed a so-called two-component reaction type rubber-modified asphalt, in which a liquid rubber having a terminal hydroxyl group is blended as a rubber component, and a curing agent having an isocyanate group is added thereto to carry out a curing reaction.■Rubber Rubber-modified asphalts have been proposed that use liquid rubber prepolymers containing incyanate groups as a component.

However, due to the fast curing speed of the above method (■), cross-contact or gelation occurs in the molding machine, making it difficult to continuously mold sheets using an extruder, etc., and compression molding is exclusively used, resulting in extremely low productivity. low. Furthermore, the workability is very poor when used as a sealant. In addition, in method (2), the curing reaction is very slow and there is no shapeability, so although it can be used as a thin layer coating agent, it is not possible to obtain thick molded products such as sheets. Furthermore, even if water is used as a curing agent, it is not compatible and is not practical.

The inventors of the present invention have conducted intensive research to eliminate these drawbacks, and have found that when a solid rubber vulcanization accelerator is added to polyisocyanate containing polydiene chains, it exhibits excellent curability. It was found that it is related only to the terminal incyanate group, regardless of the double bond in the isocyanate. The present invention was made based on this completely new knowledge and the good compatibility of polyisocyanate containing polydiene chains with asphalt, which allows the curing speed of the asphalt composition to be controlled arbitrarily, has good formability, The object of the present invention is to provide an asphalt composition applicable to various uses.

The present invention is an asphalt composition comprising (A) asphalt, (B) a polydiene chain-containing polyisocyanate or a polydiene chain-containing blocked polyisocyanate, and (C) a vulcanization accelerator.

Examples of the asphalt as component (A) used in the present invention include straight asphalt, semi-blown asphalt, blown asphalt, and mixtures thereof.

Next, in the composition of the present invention (the component of the polydiene chain-containing polyisocyanate or the polydiene chain-containing blocked polyisocyanate) is an isocyanate group-containing urethane prepolymer containing a polydiene chain in the molecular chain or the incyanate group. This is a blocked polyisocyanate to which a blocking agent for masking is bonded.In any case, the blocking agent in this blocked polyisocyanate is dissociated by heating during use of the composition, and it functions as a polyisocyanate.

Here, the above polydiene chain-containing polyisocyanate is
It is a urethane prepolymer obtained by reacting a liquid diene polymer having an active hydrogen group such as a hydroxyl group, amine group, imino group, carboxyl group, or mercapto group at the molecular end with an organic polyisocyanate compound.

These liquid diene polymers have a number average molecular weight of j
00~. :zsooo diene polymers having a carbon number of t~/2, copolymers thereof, and copolymers of these diene monomers with olefinic addition-polymerizable monomers having a carbon number of λ~ and 22. 1. Of course, it includes liquid diene polymers modified by adding an unsaturated carboxylic acid such as maleic anhydride or a derivative thereof to these liquid diene polymers. Specifically, polybutadiene homopolymer, polyisoprene homopolymer
') mer, butadiene-styrenic polymer.

Butadiene-isoprene copolymer, butadiene-acrylonitrile copolymer, butadiene-! -ethylhexyl acrylate copolymer, butadiene-n-octadecyl acrylate copolymer, and the like. Among them, the viscosity is 1,000 poise or less, more preferably 300 poise or less, and the chemical structure/, bonding is 50 poise or less.
% or more of the polymer is preferred.

In the present invention, a prepolymer is basically obtained by reacting this active hydrogen group-containing liquid tsene-based polymer with an organic polyisocyanate compound, usually a diisocyanate compound, but other active hydrogen group-containing compounds can also be used in combination. It does not limit what you can do.

Next, active hydrogen group-containing compounds that can be used in combination include ethylene glycol, propylene glycol,
, II-butanediol, glycerin I)') Methylolpropane, /, 2. g-hexanetriol,
Low-molecular polyols such as pentaerythritol, ethylene diamine, tl, +'-methylene bis! - For example, a propylene oxide adduct of bisphenol A or a polypropylene compound obtained by addition polymerizing an alkylene oxide such as ethylene oxide or propylene oxytona to an amine compound such as chloroaniline, Il, ψ-methylene-bis-2-ethylaniline, or a low-molecular polyol or amine compound. There are polyether polyols such as oxypropylene glycol, polyoxypropylene polyoxyethylene glycol, and ethylene oxide adducts of these polyols. Furthermore, it is a condensation polymer of polyhydric alcohols such as ethylene glycol, propylene glycol, Il-butanediol, etc. and polybasic acids such as phthalic acid, maleic acid, malonic acid, succinic acid, adipic acid, and terephthalic acid. Polyester polyols with hydroxyl groups at the ends, acrylic polyols, castor oil,
Examples include tall oil.

Next, examples of the organic polyincyanate compound which is reacted with the active hydrogen group-containing compound to obtain a prepolymer include tolylene diisocyanate, diphenylmethane diincyanate, hexamethylene diisonanate, polymethylene polyphenyl polyisocyanate, liquid modified Diphenylmethane diisocyanate, xysolene diisocyanate, ? , -t, cyclohexane phenylene diisocyanate, cyclohexylzoisocyanate, naphthalene/, terdiisocyanate, xylylene!
, 2'-diisocyanate, isopropylbenzene-2
, gauge incyanate, an addition reaction product of polyzolopylene glycol and tolylene diisocyanate, and an addition reaction product of 1 mole of trimethylolpropane and 3 moles of tolylene diisocyanate.

The reaction to obtain this incyanate group-containing urethane prepolymer is usually carried out at NGO 10H (equivalent ratio) of 5 or more under an inert gas flow such as dry nitrogen at a reaction temperature of 30 to 100°C and a reaction time of 70 minutes to 70 hours. It is held below. The isocyanate group content of this prepolymer is usually 2.
-20% by weight, preferably 2-75% by weight.

Component (B) of the composition of the present invention is basically the above-mentioned polydiene chain-containing polyisocyanate, but a blocking agent that masks incyanate groups to isocyanate groups of the polyisocyanate in order to improve stability during storage. It may also be a blocked polyisocyanate in which these are bonded. Here, the seven blocking agents are phenol, cresol,
Phenols such as xylenol and nonylphenol,
Alcohols such as methanol, ethanol, and impropatol; lactams such as caprolactam and butyrolactam; oximes such as acetoxime, methyl ethyl ketoxime, and cyclohexanoxime; other imides;
Examples include esters. In any case, in this blocked polyisocyanate, the blocking agent is dissociated by heating above 00'O, the free incyanate is regenerated, and the result is a polyisocyanate.

The blending amount of the polyisocyanate (B) component is as follows:
It is usually determined in a range of 3 to 300 parts by weight, preferably 5 to 150 parts by weight, based on 100 parts by weight of asphalt, which is component (A). Specifically, the use of modified asphalt,
It may be determined as appropriate depending on the required performance. However, if it is less than 3 parts by weight, the improvement in physical properties due to modification is small;
Since it becomes expensive if it exceeds parts by weight, it is usually blended within the above range.

Next, as the vulcanization accelerator which is component (C) of the composition of the present invention, dithioate salt compounds such as sodium dibutyldithiocarbamate, xanthate compounds such as zinc butylxantodate, and tetramethylthiuram disulfide are used. Examples include thiuram compounds such as NIN-dicyclohexyl-2-benzothiazolylsulfenamide, and aldehyde amine compounds such as n-butyraldehyde aniline. Among these compounds, dithioate-based and xanthate-based compounds are preferred. In addition, sodium hydroxide, if necessary,
Calcium oxide, magnesia, zinc white, etc. can also be used as vulcanization accelerating aids.

The vulcanization accelerator, component (C), is usually used in an amount of o, os-s, preferably in the range of 0.7 to 3 parts by weight, based on 100 parts by weight of component (B). The amount added is based on the amount of component (B) in the asphalt composition, the temperature at the time of blending, and the pot life when the composition is used.

It is determined as appropriate, taking into consideration the curing time, mode of use, application, etc.

Although the asphalt composition of the present invention basically consists of the above three components, it may optionally contain a plasticizer, process oil, heavy oil, etc., calcium carbonate, mica, and asbestos to reduce the viscosity.

Fillers 9 reinforcing agents such as glass fibers and organic fibers.

Stabilizers and even thermoplastic resins can be added.

The asphalt composition of the present invention has the above (A) and (B).
, obtained by sufficiently kneading component (C) and various additives added as necessary. The crosstalk temperature at this time is determined in consideration of the type of asphalt and the blending ratio of other components, but is usually between room temperature and 200C, preferably between room temperature and 200C.

The asphalt composition of the present invention is a one-component reaction type, and can be applied to thick materials such as sheets and molded products.Moreover, the curing speed can be adjusted arbitrarily, and rapid gelation does not occur. Therefore, continuous molding is possible. Furthermore, seven characteristics of the present invention include that it has excellent formability and can be easily molded, and that it can be used in applications that do not come into contact with the atmosphere (such as adhesives). Therefore, the asphalt composition of the present invention is useful as various asphalt sheets, sealants, adhesives, pressure-sensitive adhesives, and the like.

Next, the present invention will be explained in detail with reference to examples.

Examples / - B and Comparative Example / Compositions consisting of the formulations shown in Table 1 were mixed at / j 000, and the time until the resulting mixture gelled was measured. The results are shown in Table 1.

Examples 7-g and comparative examples! Compositions having the formulations shown in Table 1 were mixed at room temperature, and the approximate number of days until the resulting mixture gelled was measured. The results are shown in Table 1.

*Number average molecular weight: 2g0O, viscosity: jO voids/30°
C1 hydroxyl group content: 0. 3 meq/j7, fine structure Nidorans-/, 4': O%, Sisu/, Il: 20%,
Vinyl-/, 2:20% The blend of Example 1 was press-molded at 750°C for 30 minutes, and the blend of Example 7 was molded at room temperature to obtain a good sheet with a thickness of 2 cylinders. Obtained.

After curing for 7 days at room temperature, the physical properties of each sheet were measured.

The results are shown in Table 2.

Table 2 Tensile strength (kg/an2) Elongation Hardness Shore A) Example / 23 / DoO Otsu 0 Example 7
The /20 2 Otsu 14-

Claims (1)

[Claims] 1. An asphalt composition comprising (A) asphalt, (B) a polyisocyanate containing a polydiene chain or a blocked polyinsyanate containing a polydiene chain, and (C) a vulcanization accelerator. 2. (A) 100 parts by weight of asphalt, (B) 3 to 300 parts by weight of polyisocyanate containing polydiene chains or blocked polyinsyanate containing polydiene chains, and (C) vulcanization accelerator per 700 parts by weight of component (B). ,OS~! Claim 1 consisting of parts by weight
The asphalt composition described in .