JPH10273572A - Sealing agent for flexible polyvinyl chloride waterproof sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a sealing agent which is easily applicable, is reduced in plasticizer volatilization after being applied, can give a seal and an area around it kept flexible for a long time and is reduced in crack formation and V-notch formation by mixing a solute component comprising a polyvinyl chloride resin having a degree of polymerization in a specified range with a plasticizer and a stabilizer with a solvent component in a specified ratio. SOLUTION: The degree of polymerization of the polyvinyl chloride resin is in the range from 400 to a degree of polymerization lower than that of the waterproof sheet to be sealed by 200. The amount of the plasticizer added is in the range from the lower limit larger than the amount of the plasticizer used per 100 pts.wt. resin of the waterproof sheet to be sealed by 10 pts.wt. to the upper limit of 100 pts.wt. It is desirable to adjust the viscosity of the sealing agent during production to 1,000-4,500 cP by using the solvent component. The solvent component is exemplified by tetrahydrofuran, methyl ethyl ketone, chlorobenzene or methyl propyl ketone.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing agent used for sealing a stretched flexible polyvinyl chloride waterproof sheet laid as a roof material or the like on a building surface of a building structure.

[0002]

2. Description of the Related Art Generally, when a flexible polyvinyl chloride waterproof sheet is stretched, a solution type sealing agent is used for the purpose of sealing the sheet.

Conventionally, in order to sufficiently integrate the sealing agent of this type with a soft polyvinyl chloride waterproof sheet to be sealed, the component after the solvent component has volatilized and solidified after the coating is used. Either a resinous solution containing pellets solute as a solute component or a resinous solution obtained by pulverizing the sheet itself and dissolving it in an appropriate solvent is used.

However, as shown in FIG. 1, in the case of using the above-mentioned conventional sealing agent, the sealing portion (S) after the sealing agent is applied and solidified, seals from the soft polyvinyl chloride waterproof sheet (A). The transfer of the plasticizer to the stop portion (S) occurs over the years, and the portion (a) of the sheet (A) adjacent to the sealing portion (S) becomes another portion (b) of the sheet (A).
As compared with the above, the reduction of the plasticizer due to volatilization is faster, the flexibility is lost, and the time required for embrittlement is reduced.

[0005] Among the above-mentioned sealing agents, particularly, those in which a sheet of the same quality as the soft polyvinyl chloride waterproof sheet itself is dissolved, the flexibility of the sealing portion (S) after being applied and solidified has the original flexibility. A phenomenon occurs in which the plasticizer is lower than that of the sheet, and the transfer of the plasticizer from the adjacent portion (a) of the sheet (A) to the sealing portion (S) is accelerated. Then, from such a phenomenon, the adjacent portion (a) of the soft polyvinyl chloride waterproof sheet (A) adjacent to the sealing portion (S)
Becomes harder over time than the other portion (b), and the sealing portion (S) becomes harder than the adjacent portion (a).

In general, as shown in FIG. 1, a soft polyvinyl chloride sheet laid outdoors for this kind of application is affected by the ultraviolet rays in the sunlight, and as a result, the surface of the polyvinyl chloride sheet ages. It is known that innumerable fine surface cracks (c) are generated starting from molecular breakage of a resin. In particular, in the adjacent portion (a) close to the sealing portion (S), during the solidification process of the sealing portion (S), the influence of the solvent contained in the sealing agent and the plasticizer of the sealing portion (S) Due to the propagation of the contraction stress generated by volatilization, the surface cracks (c) are densely generated and easily continuous with each other, and further, reach the inner layer of the sheet (A) and sometimes reach the back surface. Such a groove-shaped crack having a continuous V-shaped cross section (hereinafter referred to as a V-notch).
(D) occurs along the sealing portion (S), which causes water leakage at the end of the durability of the sheet (A).

As described above, in order to prevent the shrinkage stress from concentrating on the adjacent portion (a) over time, the sealing portion (S) is always more flexible than the soft polyvinyl chloride waterproof sheet (A). It is necessary to be. For this reason, increasing the amount of the plasticizer added as a sealing agent is one means, but this means alone can secure the initial flexibility, but the flexibility over time is not always sufficient, and Since the diffusion coefficient at the time of volatilization of the plasticizer does not change, the diffusion rate of the plasticizer increases, and the amount of the plasticizer eluted into rainwater or the like also increases. (A) The contraction stress is increased. Further, the amount of the organic solvent required to secure the workability as a sealing agent can be reduced to some extent only by the means for increasing the amount of the plasticizer, but the adverse effect of the organic solvent on the waterproof sheet (A) is eliminated. However, the effect of suppressing the occurrence of the V notch (d) is not large.

Therefore, conventionally, as a sealing agent for solving the above-mentioned problems, the amount of volatilization or elution of the plasticizer after application is smaller than that of a soft polyvinyl chloride waterproof sheet, and even after aging. The sealing portion is a sealing agent that does not reduce the flexibility of the adjacent portion of the sheet adjacent to the sealing portion, and the content ratio of the organic solvent contained in the sealing agent, with respect to the polyvinyl chloride resin as a solute component There is a need for a sealing agent that is smaller in size, delays the time of occurrence of surface cracks, and suppresses or reduces the degree of occurrence.

The present invention has been made in order to address the above-mentioned situation relating to the sealing of a flexible polyvinyl chloride waterproof sheet, and to solve the problem. If the degree of polymerization of vinyl chloride resin is reduced to the minimum necessary, the amount of organic solvent that is the solvent component of the sealing agent for waterproof sheets is used less than before, and the amount of plasticizer is increased appropriately, It has been found that it is possible to secure a sealing agent having an optimum viscosity which does not hinder the sealing work of the waterproof sheet in (1), and to reduce the long-term adverse effect of the organic solvent on the waterproof sheet.

[0010]

SUMMARY OF THE INVENTION In accordance with the present invention, in the sealing of a soft polyvinyl chloride waterproof sheet to be laid under the above-mentioned background, the work such as sealing work is easy,
The amount of volatilization or elution of the plasticizer after application is smaller than that of the waterproof sheet, the sealing part and the flexibility of the waterproof sheet adjacent thereto are maintained over time, and the sealing part of the waterproof sheet is used. An object of the present invention is to provide a sealing agent for a flexible polyvinyl chloride waterproof sheet that suppresses or reduces the occurrence of surface cracks densely at adjacent portions and suppresses or reduces continuation of each other, and suppresses or delays the occurrence of V notches. .

[0011]

In order to solve the above-mentioned problems, the present invention provides a solute component and a solvent component, wherein the main solute components are a polyvinyl chloride resin, a plasticizer and a stabilizer, and the solvent component is a specific organic solvent. In a sealing agent for a flexible polyvinyl chloride waterproof sheet, the degree of polymerization of the polyvinyl chloride resin is in the range of 400 to 200 lower than the resin degree of polymerization of the flexible polyvinyl chloride waterproof sheet to be sealed. The gist of the present invention is a sealing agent for a soft polyvinyl chloride waterproof sheet.

The polyvinyl chloride resin, which is the main solute component of the present invention, is not particularly limited in type,
A homopolymer of vinyl chloride and a copolymer of vinyl chloride with vinyl acetate, ethylene, propylene, or the like, or a mixture of two or more thereof can be suitably applied.

By the way, as a soft polyvinyl chloride waterproof sheet generally laid as a roof material or the like, a polyvinyl chloride resin as a resin component having a degree of polymerization of about 1300 to 1800 is used.

On the other hand, in the present invention, the polymerization degree of the polyvinyl chloride resin as the main solute component is from 400 to 200 from the resin polymerization degree of the soft polyvinyl chloride waterproof sheet.
It was in the range of low polymerization degree. This means that the degree of polymerization is 40
If it is less than 0, the durability becomes extremely low, which is not preferable.
If the degree of polymerization exceeds 0, the amount of the organic solvent as the solvent component cannot be reduced, which is inconvenient. Therefore, preferably, the polymerization degree of the resin used in the waterproof sheet is 50 to 70.
% Is preferred.

Further, one preferred embodiment of the present invention is as follows.
The lower limit of the amount of the plasticizer added as a solute component is 10 parts by weight greater than the amount of the plasticizer with respect to 100 parts by weight of the resin of the soft polyvinyl chloride waterproof sheet to be sealed. The sealing agent for a flexible polyvinyl chloride-based waterproof sheet according to claim 1, wherein the upper limit is in the range of 100 parts by weight.

If the amount of the plasticizer in the soft polyvinyl chloride waterproof sheet is less than the above lower limit, not only the flexibility of the sealed portion cannot be maintained over time, but also the reduction of the organic solvent cannot be achieved, and the above upper limit cannot be achieved. Exceeding the value undesirably increases the contraction stress of the sealing portion and the adjacent portion of the adjacent waterproof sheet. Therefore, the amount is preferably 20 parts by weight or more, more preferably 90 parts by weight or more than the amount of the plasticizer based on 100 parts by weight of the resin of the flexible polyvinyl chloride waterproof sheet.

Further, another preferred embodiment of the present invention is as follows.
By the solvent component consisting of a specific organic solvent, the viscosity at the time of production is adjusted to the range of 1000 to 4500 cP,
The sealant for a flexible polyvinyl chloride waterproof sheet according to any one of claims 1 to 2.

Generally, a sealing agent for a flexible polyvinyl chloride waterproof sheet has a viscosity of 500 to 30,000 c.
If it is in the range of P, it can be applied to the sealing work of the waterproof sheet, and is not an exception in the present invention. As described above from 1000 to 4500
It is desirable to adjust to the range of cP.

The organic solvent used here may be a single or mixed solvent of tetrahydrofuran, methyl ethyl ketone, 1,2-dichloroethane, chlorobenzene, dichloromethane, methyl propyl ketone, cyclohexanone, etc. The sealing agent can be applied very easily in the sealing operation of the soft polyvinyl chloride waterproof sheet.

The solute component of the sealing agent for the flexible polyvinyl chloride waterproof sheet of the present invention includes, in addition to the above-mentioned polyvinyl chloride resin and plasticizer, calcium zinc-based, tin-based, barium zinc-based, lead System and other stabilizers can be added, and various colorants and various additives can be added as solute components,
It can be added together with the solvent component.

[0021] As described above, the sealing agent for a flexible polyvinyl chloride waterproof sheet of the present invention is a resin for a flexible polyvinyl chloride waterproof sheet whose degree of polymerization of a polyvinyl chloride resin as a solute component is to be sealed. The degree of polymerization is set in accordance with the degree of polymerization.
Those having a degree of polymerization of 400 to 1100 for those having a value of 00, and those having a degree of polymerization of 400 to
1600 applies. Therefore, when adjusting the viscosity of the sealing agent, the amount of the organic solvent as the solvent component can be reduced within the range of the appropriate viscosity.

In the present invention, the lower limit of the amount of the plasticizer added as a solute component is 10 parts by weight larger than the amount of the plasticizer with respect to 100 parts by weight of the resin of the soft polyvinyl chloride waterproof sheet to be sealed. And the upper limit is set in the range of 100 parts by weight. For example, when the waterproof sheet has a plasticizer amount of 60 parts by weight, the plasticizer amount is 70 to 10 parts by weight.
It is in the range of 0 parts by weight, preferably 80 to 90 parts by weight.
Therefore, the increase in the amount of the plasticizer, combined with the use of the polyvinyl chloride resin having a low degree of polymerization, makes the above-mentioned reduction in the amount of the organic solvent effective, and furthermore, the sealing part after aging and the waterproof part adjacent thereto are aged. It greatly contributes to maintaining the flexibility of the seat.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described.
A description will be given along with Examples and Comparative Examples based on an experiment for producing a sealing agent and an accelerated weathering test.

[Preparation Experiment] First, the components shown in Table 1 were prepared as the components used in the sealing agent for the soft polyvinyl chloride waterproof sheet.

[0025]

[Table 1]

Examples 1 to 7 From the components shown in Table 1 above, for each of Examples 1 to 7,
Each of the pellet raw materials having the component ratios shown in Table 2 was blended and dry-blended with a Henschel mixer, and then a sheet having a thickness of 0.5 mm was produced using two kneading hot rolls.

Further, after the above-mentioned sheet is pulverized into pellets, tetrahydrofuran having the highest solubility in soft polyvinyl chloride as an organic solvent and cyclohexanone having an effect of reducing the volatilization rate of the solvent are added in the following proportions: The pellets were dissolved using a mixed solvent mixed at a volume ratio of 1 and the viscosity of the solution at room temperature was 3500 c.
The amount of the mixed solvent was adjusted to be P. Obtained viscosity 3
A solution of 500 cP was prepared as a sealing agent. Table 2 also shows the workability of the pellet sheet and the amount of solvent required for 100 parts by weight of the pellets.

As described above, in the preparation of the sealing agents according to Examples 1 to 7, the workability of the pellet sheet is good, and the amount of the required mixed solvent is as small as 210 parts by weight or less. Was something.

[0029]

[Table 2]

Comparative Examples 1 to 6 Next, in the same manner as in the above Examples, from each component shown in Table 1, for each of Comparative Examples 1 to 6, a pellet material having a component ratio shown in Table 2 was blended. Similarly, an attempt was made to produce a sealing agent composed of each component.

As a result, among the above comparative examples, comparative examples 1 to
In Table 3, as also shown in Table 2, the workability of the pellet sheet was good (（), but in Comparative Example 4, the dry-up was incomplete during dry blending, which was somewhat difficult (△). was there. Further, as for the amount of the organic solvent, all of Comparative Examples 1 to 4 required an amount of the organic solvent exceeding 210 parts by weight. It should be noted that in Comparative Example 5, the workability was remarkably poor such that the roll could not be formed by sticking to the roll when the sheet was formed, and in Comparative Example 6, the dry-up could not be performed during dry blending (× ) No pellet was obtained, and thus a comparative sample of the sealing agent could not be obtained.

[Accelerated weathering test] Using each of the above sealing agents obtained in Examples 1 to 7 and Comparative Examples 1 to 4,
As shown in FIG. 2, the edges of two flexible polyvinyl chloride-based waterproof sheets (A) and (A) are overlapped, and the overlapped portions are joined by a solvent, and the respective ends are attached to the upper end of the waterproof sheet. After applying the sealing agent, a sealed sample piece (T) having a sealed portion (S) formed therein was produced. The soft polyvinyl chloride waterproof sheet (A) is composed of 100 parts by weight of polyvinyl chloride having a resin polymerization degree of 1300, 60 parts by weight of a linear alcohol phthalate as a plasticizer, and organic tin maleate 2 as a stabilizer. A sheet obtained by an extrusion molding method comprising 0.2 parts by weight and 7.5 parts by weight of titanium oxide as a filler, and is substantially composed of the same components as in Comparative Example 2.

An accelerated weathering test was performed on each of the above sealed test pieces (T) by the following test method.

[Test method]: Dew panel light control weatherometer (DPWL-5R manufactured by Suga Test Instruments Co., Ltd.)
Type) exposure test. Cycle: [black panel temperature 80 ° C x fluorescent ultraviolet irradiation x 4 hours] + [black panel temperature 50 ° C x humidity 90]
% RH × 4 hours] as one cycle. Exposure time: 1500 hours, and 2500 hours.

For each sample after the test, the state of crack occurrence was measured by measuring the notch width of a V-shaped notch, and those having a notch width of less than 0.015 mm were determined to have good weather resistance.
Those having a size of 015 mm or more were evaluated as having poor weather resistance.

As a result, as shown in Table 3, the weather resistance of all of Examples 1 to 7 was good (７). However, Comparative Examples 1 to 4 were all poor (x).

[0037]

[Table 3]

[0038]

As described above, the sealing agent according to the present invention comprises a solute component and a solvent component, the main solute components being a polyvinyl chloride resin, a plasticizer and a stabilizer, and the solvent component being a specific organic solvent. In a sealing agent for a flexible polyvinyl chloride waterproof sheet, the degree of polymerization of the polyvinyl chloride resin is set in a range of 400 to 200 lower than the resin polymerization degree of the flexible polyvinyl chloride waterproof sheet to be sealed. Therefore, within the range of the appropriate viscosity, it is possible to reduce the amount of the organic solvent as a solvent component of the sealing agent, reduce the fine surface roughening by the organic solvent on the sheet adjacent to the sealing portion, sealing, This has the effect of suppressing the occurrence of surface cracks densely in the adjacent portion of the stop portion and the continuation of each other.

In the present invention, the lower limit of the amount of the plasticizer as a solute component is 100 parts by weight of the polyvinyl chloride resin, and the lower limit is 100 parts by weight of the resin of the flexible polyvinyl chloride waterproof sheet to be sealed. 10 from the amount of plasticizer per part
By weight, and the upper limit can be set in the range of 100 parts by weight, together with the application of the polyvinyl chloride resin having a low degree of polymerization, while effectively reducing the amount of the organic solvent, There is an effect of maintaining the flexibility of the sealing portion after the application of the sealing agent for a long period of time and preventing the aging shrinkage stress of the waterproof sheet from concentrating on the adjacent portion of the sealing portion,
Surface cracks occur densely in the adjacent part,
The above effect of suppressing continuation of each other can be promoted.

Therefore, according to the sealing agent for a flexible polyvinyl chloride waterproof sheet of the present invention, the waterproof sheet is provided with a sealant for the flexible polyvinyl chloride waterproof sheet laid outdoors. It is possible to suppress or reduce the occurrence of the V-notch which causes a cause, or to significantly delay the occurrence.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a state in a sealed portion of a conventional soft polyvinyl chloride waterproof sheet laid.

FIG. 2 is a perspective view showing a state of a sample piece applied to an accelerated weathering test of an example.

[Explanation of symbols]

 A: Soft polyvinyl chloride waterproof sheet S: Sealed part a: Adjacent part b: Other part c: Surface crack d: V notch T: Sealed specimen

Claims (3)

[Claims] 1. A sealing material for a flexible polyvinyl chloride waterproof sheet, comprising a solute component and a solvent component, wherein the main solute components are a polyvinyl chloride resin, a plasticizer and a stabilizer, and the solvent component is a specific organic solvent. Sealing for a soft polyvinyl chloride waterproof sheet, wherein the degree of polymerization of the polyvinyl chloride resin is in the range of 400 to 200 lower than the resin polymerization degree of the soft polyvinyl chloride waterproof sheet to be sealed. Agent. 2. A soft polyvinyl chloride-based waterproof sheet having a lower limit of 100 parts by weight of a plasticizer as a solute component, based on 100 parts by weight of the polyvinyl chloride resin.
The sealing agent for a flexible polyvinyl chloride waterproof sheet according to claim 1, wherein the amount is 10 parts by weight larger than the amount of the plasticizer based on parts by weight, and the upper limit is in the range of 100 parts by weight. 3. The sealing agent for a flexible polyvinyl chloride waterproof sheet according to claim 1, wherein the viscosity is adjusted to a range of 1000 to 4500 cP using a specific organic solvent as a solvent component.