JPH075840B2 - Asphalt composition for waterproof sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention is not a by-product produced as a by-product during the production of isotactic polypropylene, but has a number average molecular weight in the range of 1,000 to 20,000, which is a target product. Content is 2-8
The present invention relates to an asphalt composition for a waterproof sheet, which comprises an amorphous propylene / ethylene random copolymer and asphalt as the main components in an amount of less than wt%.

The asphalt composition for a waterproof sheet of the present invention is inexpensive and has excellent performance, and thus is widely used as a sealing material between concrete plates in a building, a railway, a road, etc., a joint sealing material such as a water pipe, a roof waterproofing, etc. It is particularly suitable for a waterproof sheet for the torch method.

[Prior Art] Asphalt-based waterproof compositions are known in which asphalt is mixed with various raw rubbers such as natural rubber, butyl rubber, styrene-butadiene rubber, thermoplastic elastomers or resins such as atactic polypropylene and petroleum resin. There is. Especially, "Waterproof Journal" 1986
In November 2012, p. 112, the torch construction method and the torch are to use a torch-shaped gas burner as a tarpaulin for roofs and rooftops to simultaneously apply the sheet to the back and base of a single-ply tarpaulin with a thickness of about 4 mm at the same time. A waterproof sheet for a construction method is described, and an example in which atactic polypropylene / styrene / budadiene / styrene block copolymers are separately used for asphalt modification is described.

[Problems to be Solved by the Invention] However, these known compositions still have problems in changes in physical properties due to temperature changes in summer and winter, recoverability against deformation, and workability due to changes in viscosity during work.

In particular, regarding the waterproof sheet for the torch method, the waterproof sheet modified by adding styrene / budadiene / styrene block copolymer (SBS) to the asphalt makes it difficult to mix asphalt and SBS, and the viscosity of the asphalt increases. Since it is too much, it is not possible to increase the amount of SBS compounded. Even if it is added in a small amount, it is excellent in low-temperature flexibility, but it softens significantly in the high-temperature range, making it difficult to use in the warm and heat zones.

On the other hand, since a tarpaulin modified with atactic polypropylene can be easily compounded in a large amount, it does not soften at high temperatures, but this atactic polypropylene is a by-product during the production of crystalline isotactic polypropylene resin. It is a low-molecular-weight amorphous polymer that can be used as a waterproof sheet for the torch method because it is inexpensive and has a low viscosity and is a by-product residue of crystalline polypropylene.However, some drawbacks are also included. have.

That is, there are three types of crystalline isotactic polypropylene: homopolymer, random copolymer, and block polymer, but the composition is either propylene alone or at most 5% even if ethylene is copolymerized in the random copolymer. As a by-product, atactic polypropylene also contains about 5 to 6% of ethylene.

As described above, since the atactic polypropylene produced as a by-product from the homopolypropylene and the random copolymer contains propylene as a main component, it was difficult to obtain a product having good low temperature characteristics. On the other hand, in the amorphous polypropylene produced as a by-product from the block copolymer, the rubber component to be extracted contains a large amount of ethylene but is not a random copolymer, so the components are not uniform and sticky or the quality is not constant. Low utility value.

For these reasons, it was difficult to obtain atactic polypropylene having good low temperature characteristics and high utility value.

In addition, since it is a by-product residue, it is difficult to produce the required amount by limiting the properties such as viscosity, softening point, hardness, etc. The molecular weight of by-product atactic polypropylene depends on the molecular weight of crystalline isotactic polypropylene. As a result, the desired melt viscosity could not be obtained. Also,
Since a solvent is used when separating atactic polypropylene from crystalline isotactic polypropylene, it is difficult to completely remove the solvent and to remove the catalyst residue. Further, as the isotactic polypropylene catalyst shifts to a highly active type, the amount of by-produced atactic polypropylene produced is decreasing, and there is concern about stable availability for the future.

Since the waterproof sheet in which the by-product atactic polypropylene having the above-mentioned drawbacks is blended as the main component of the modifier is inferior in flexibility at low temperature, cracking is likely to occur during construction or use at low temperature. It has drawbacks such as odor and ignition risk due to residual solvent, softening point, and melt viscosity being difficult to keep within a certain quality range. And in the future,
There is a problem because there is concern that production will be stopped because raw materials cannot be secured.

Therefore, the present inventors have found that the purpose-produced amorphous propylene / ethylene random copolymer having an ethylene content of 8 to 30% by weight, which cannot be obtained by a by-product of isotactic polypropylene, has the low temperature characteristics and the above-mentioned drawbacks. The inventors have found that they have overcome the problems and have already filed an application for a tarpaulin asphalt composition using the polymer as Japanese Patent Application No. 63-112065.

However, when the ethylene content is 8 to 30% by weight, the low temperature characteristics of the asphalt composition for a waterproof sheet made of the polymer are good and the hardness up to about 40 ° C is not a problem, but the waterproof sheet has a higher temperature than that. For example, immediately after the completion of heating construction of the torch method, or when exposed to direct sunlight in the summer, the degree of softening is large, when the footprints when a person walks on the seat or local load is applied. It was found that there was a problem with the dents and the sagging of the vertical sheet.

[Means for Solving the Problems] Therefore, an object of the present invention is to eliminate the drawbacks of these known waterproofing material compositions, and in particular, low temperature flexibility, heat resistance, dent resistance at high temperature, sagging resistance, workability. Another object of the present invention is to provide an asphalt composition for a waterproof sheet having excellent quality stability, particularly an asphalt composition suitable for a waterproof sheet for a torch method.

That is, the waterproofing sheet asphalt composition according to the present invention has a number average molecular weight of 1, which is a target product, not a by-product produced during the production of isotactic polypropylene.
For a waterproof sheet in which 100 to 1900 parts by weight of asphalt is mixed with 100 parts by weight of an amorphous propylene / ethylene random copolymer having an ethylene content of 000 to 20,000 and an ethylene content of less than 2 to 8% by weight. It is an asphalt composition.

The amorphous propylene / ethylene random copolymer used in the present invention is copolymerized by introducing ethylene into liquefied propylene in the presence of hydrogen using a titanium-supported catalyst supported on magnesium chloride and triethylaluminum. It is an amorphous random copolymer having a number average molecular weight of 1,000 to 20,000, preferably 1,500 to 18,000 and an ethylene content of 2 to 8% by weight.
Since the ethylene content of this polymer is in the above range,
It has good heat resistance of atactic polypropylene, good low-temperature characteristics, but relatively high softening point.
Penetration is small, and properties such as softening point and melt viscosity can be kept within a certain range to produce stable quality. Further, it is possible to produce by setting the softening point and the melt viscosity to constant values depending on the copolymerization ratio of propylene and ethylene and the molecular weight. Further, since the polymerization is carried out without using a solvent and there is no treatment step with a solvent, there is no risk of ignition or odor.

When the number average molecular weight of the amorphous propylene / ethylene random copolymer is less than 1,000, the asphalt modification effect is not sufficient, while when it is more than 20,000, the melt viscosity is too high and it is difficult to mix with asphalt. become. Further, if the amorphous propylene / ethylene random copolymer having an ethylene content of less than 2% cannot be expected to have improved low-temperature properties, on the other hand, if it has an ethylene content of more than 8%, the hardness at room temperature is sufficient, but at 60 ° C. It cannot be used for high temperature heat resistance because it becomes too soft under the above high temperature.

The asphalt referred to in the present invention may be straight asphalt or blown asphalt,
Straight asphalt is preferable because it is easily mixed with the amorphous propylene / ethylene random copolymer and is inexpensive. Straight asphalt here is defined in JIS K2207,
It has a softening point of 30 to 90 ° C, preferably 35 to 80 ° C.

The blending ratio in the composition of the present invention is such that amorphous propylene
The amount of asphalt is 100 to 1900 parts by weight, preferably 120 to 1600 parts by weight, based on 100 parts by weight of the ethylene random copolymer. If it is less than 100 parts by weight, the amount of asphalt component is small,
It is inferior in water resistance, cheapness, and workability, which are the characteristics of asphalt, and conversely, when it exceeds 1900 parts by weight, low temperature properties become inferior.

In the composition of the present invention, one or more kinds of synthetic rubber, polyolefin polymer and thermoplastic elastomer can be blended, if necessary.

By blending these polymers, the impact resistance of the waterproof sheet can be increased, but amorphous propylene / ethylene random is used because of the miscibility with asphalt and especially the fluidity of the waterproof sheet for the torch method. It is preferably 20 parts by weight or less with respect to 100 parts by weight of the composition comprising the copolymer and asphalt. If too much, it becomes difficult to dissolve when mixed with asphalt.

Styrene / butadiene copolymer rubber (SBR), isoprene rubber (IR), butadiene rubber (B
R), neoprene rubber (NPR), ethylene / propylene copolymer rubber (EPR), ethylene / propylene / diene rubber (EPDM) and butyl rubber. The polyolefin polymer is a copolymer containing polyethylene, polypropylene, polybutene and ethylene as main components, that is, ethylene and olefins such as propylene, butene, pentene, hexene, heptene and octene,
One or more comonomers selected from vinyl esters such as vinyl acetate and vinyl propionate, unsaturated carboxylic acid esters such as methyl acrylate, ethyl acrylate, methyl methacrylate, and ethyl methacrylate, and ionomers thereof. And a multi-component copolymer.

As the thermoplastic elastomer, styrene / butadiene / styrene block copolymer (SBS), styrene / isoprene / styrene block copolymer (SIS), styrene / ethylene / butylene / styrene block copolymer (SE
BS) and the like.

Further, in the present invention, calcium carbonate as a filler,
Inorganic fillers such as aluminum hydroxide, clay, and talc can be added appropriately depending on the application.

In the present invention, the method of mixing the amorphous propylene / ethylene random copolymer, asphalt and other additives can be carried out by a conventionally known method, for example, after heating and melting the asphalt in a mixing pot, the amorphous It can be carried out by adding a soluble propylene / ethylene random copolymer and, if necessary, other additives and dissolving and mixing until homogeneous.

The composition of the present invention can be used alone or as a waterproof sheet by impregnating, coating or pressure-bonding the asphalt composition on a roofing base paper, woven or non-woven fabric, metal thin plate or foil.

The roofing base paper is made of organic or inorganic material such as asbestos felt, asbestos roofing, and perforated felt, and the woven or non-woven fabric is made of glass fiber type, nylon type, vinylon type, polyester type, fiber type inorganic or the like. The organic long fibers or short fibers are used, and examples of the metal thin plate or foil include copper, iron and aluminum.

The waterproof sheet of the present invention is waterproof, moisture proof, heat insulating, sound absorbing, shock absorbing, stretchable, electrical insulating, weather resistant, chemical resistant,
Since it has excellent heat resistance and low-temperature flexibility, it can be suitably used for various applications, especially for roofing materials for the torch construction method.

The waterproof sheet has a thickness of 0.2 to 10 mm, preferably 0.5 to
It is 8 mm, particularly preferably 1 to 6 mm. If it is too thin, the waterproof effect is not sufficient, and if it is too thick, the construction is difficult. Especially in the case of the roofing material for the torch construction method, the back side of the sheet is heated and melted while it is rewound and pasted, so if it is extremely thin, the sheet melts and cuts, and if it is extremely thick, rewinding and heating work at the same time. I can't.

[Effects of the Invention] As described above, the asphalt composition for a waterproof sheet of the present invention has the following effects.

The low-temperature flexibility of the waterproof sheet has been improved so that no cracks or cracks will occur during low-temperature work or after construction.

Since the amorphous propylene / ethylene random copolymer has a high softening point and a low penetration, it is possible to prevent dents and sagging of vertical parts due to the load when the compounded waterproof sheet is exposed to high temperatures. .

Since the amorphous propylene / ethylene random copolymer and asphalt have a good mixing property, a large amount of the propylene / ethylene random copolymer can be blended, so that the composition can be prevented from softening and flowing at high temperature. .

It is possible to obtain a waterproof sheet having various properties such as quality-controlled softening point, hardness and fluidity.

There is no risk of odor or ignition due to solvent during manufacturing, construction or use.

[Examples] Examples 1 to 4 and Comparative Examples 1 and 2 <Materials used> (A) Amorphous propylene / ethylene random copolymer Ti-supported catalyst (Ti-containing) supported on magnesium chloride in an autoclave equipped with a stirrer 2.4 wt%) and a triethylaluminum catalyst system (Al / Ti molar ratio = 100) in the presence of hydrogen as a molecular weight regulator at 80 ° C. by adjusting the amount of ethylene introduced into liquefied propylene An amorphous propylene / ethylene random copolymer was produced. The ethylene content and number average molecular weight at this time were as follows.

Sample Ethylene content Number average molecular weight Copolymer-1 3.5% by weight 7,200 Copolymer-2 7.0% by weight 7,100 Copolymer-3 14.2% by weight 7,400 (B) Styrene / butadiene / styrene block copolymer: Kali manufactured by Shell Chemical Flex TR (C) Asphalt: Nippon Oil Co., Ltd. straight asphalt 80/100 <Composition method of composition> Take asphalt in a mixing vessel, mix while heating,
When the temperature reached 180 ° C., an amorphous propylene / ethylundum copolymer and a styrene / butadiene / styrene block copolymer were added at the compounding ratio shown in Table 1 and mixed and dissolved for 30 minutes to obtain a composition. The physical properties of these were measured by the following measuring methods. The results are shown in Table 1.

<Measurement methods of physical properties> (A) Penetration: Measured at 60 ° C according to JIS K2207.

(B) Number average molecular weight: GPC method, 135 ° C., solvent ODCB.

(C) Ethylene content: NMR method.

(D) Low-temperature flexibility: The composition was press-molded into a sheet having a thickness of 2 mm and wound around a bar having a diameter of 10 mm in an atmosphere of -10 ° C, and it was confirmed whether or not it was broken. Displayed by the number of broken samples / the number of test samples.

(E) (Melt index): JIS K7210 compliant, 60 ° C
Measured at 80 ℃ and 16Kg load.

Claims (1)

[Claims] 1. An asphalt of 100 to 1900 based on 100 parts by weight of an amorphous propylene / ethylene random copolymer having a number average molecular weight of 1,000 to 20,000 and an ethylene content of 2 to less than 8% by weight. An asphalt composition for a waterproof sheet, which is blended by weight.