JPH0471116B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to the improvement of a vinyl chloride sol sealer used for welding joints of automobile bodies and the like. [Prior Art] PVC sol sealer is used for spot welding joints in vehicles. As such vinyl chloride sol sealers, there are known ones that have flow properties, those that have almost no flow properties, and those that have thermal foamability depending on the location where they are applied. A PVC sol sealer with thermal flow properties is described in JP-A-57-180678, and a thermal-expandable one is described in JP-A-55-180678.
No. 92779 etc. are known. [Problem to be solved by the invention] Conventional PVC sol sealers satisfy either thermal flowability or thermal foamability, but no one is known that has both thermal flowability and thermal foamability. . An object of the present invention is to provide a new vinyl chloride sol sealer that has both thermal flowability and thermal foamability, and has excellent sealer flowability and sealing properties, that is, good workability and sealing properties as a sealer. [Means for Solving the Problem] As a result of detailed study of the flowability and foamability of the PVC sol sealer, the inventor found that the flowability of the foamed sealer is extremely poor and that the flowability decreases due to gelation. It was confirmed. From the viewpoint of workability and sealability, it was confirmed that it is preferable to flow first and then foam. The inventor focused on temperature as a method of giving PVC sealer different functions based on the passage of time. When heating an object, the temperature of the object usually increases as the heating time increases. That is, we focused on the fact that in the early stage of heating, the temperature is low because the object is not sufficiently heated, and in the latter stage of heating, the temperature becomes high because the object is sufficiently heated. They have discovered that an ideal PVC sealer can be obtained by exhibiting a flow function when the temperature is relatively low in the early stage of heating, and by exhibiting a foaming function in the latter stage of heating, that is, when the temperature reaches a predetermined temperature. The present inventor has determined that, when the total weight is 100%, 5 to 50% by weight of a base resin consisting of a vinyl chloride resin or a copolymer resin with vinyl chloride having an average degree of polymerization of 500 to 3000, and one or more Temperature-sensitive thixotropic agent 0.1-10
% by weight and 0.1-10% by weight of thermally expandable particles, at room temperature 30
The flow properties per minute are 10mm or less both horizontally and vertically, the flow properties are 50mm or more horizontally and 100mm or more vertically at 110℃ for 30 minutes, and the thermal expansion is 50mm or less at 110℃ for 10 minutes. % or less, and 50% or more at 140℃ for 30 minutes. The main components of the vinyl chloride sol sealer of the present invention are a base resin, a temperature-sensitive thixotropic agent, and thermally expandable particles. Base resin is vinyl chloride resin or copolymer resin with vinyl chloride, and usually has an average degree of polymerization of about 500~
3000 are used. 100% total sheera by weight
In this case (the same applies hereinafter), the blending amount of the base resin is 5 to 50% by weight, more preferably 15 to 30% by weight. As is well known in the industry, the temperature-sensitive thixotropic agent imparts flow properties to the sealer at a predetermined heating temperature. It is the same as the imparting agent. As such temperature-sensitive thixotropic agents, hydrogenated oils such as hydrogenated linseed oil and hydrogenated castor oil, and thermoplastic resins such as low-melting polyethylene can be used. These temperature-sensitive thixotropy imparting agents can be blended alone into the base resin, or a plurality of temperature-sensitive thixotropy imparting agents may be used in combination. The blending ratio of the temperature-sensitive thixotropic agent is 0.1 to 10% by weight, more preferably 0.5 to 7% by weight. Thermal expandable particles are the same as those used in conventional PVC sealers with foaming properties, such as the thermal expandable particles containing volatile fluid blowing agents described in JP-A-42-26524. They are plastic polymer particles. These thermally expandable particles expand when the volatile fluid is gasified by heating, and at the same time, the capsule-shaped thermoplastic polymer containing the volatile fluid softens.
It expands due to the pressure of the residue. Various types of thermally expandable particles are known that can foam at any temperature depending on the boiling point of the volatile fluid contained therein. In the present invention, in a state where it is blended with PVC sol sealer
Thermal expandable particles are used that have an expansion property of 50% or less at 110°C for 10 minutes and an expansion property of 50% or more at 140°C for 30 minutes. The blending ratio of thermally expandable particles is approximately 0.1 to 10% by weight. More preferably, it is 3 to 7% by weight. Fillers such as calcium carbonate, talc, zinc white, titanium oxide, clay, kaolin, silica, and alumina can be used in the vinyl chloride sol sealer of the present invention in an amount of 20 to 60% by weight. Phthalate esters such as DOP and DIDP are preferred as plasticizers, and DOA, BPBG, DOZ,
Polyester plasticizers such as DOS, adipic acid, trimellitic acid, and phthalic acid can also be used. These plasticizers can be used in proportions of 5 to 50% by weight. As other additives, it is possible to increase or decrease the amount of flow during heating by using 0.1 to 30% by weight of a well-known non-temperature-sensitive thixotropic agent. These non-temperature-sensitive thixotropic agents include hydrated silicic acid, anhydrous silicic acid,
Organic bentonite and ultrafine calcium carbonate are known. Furthermore, adhesion imparting agent
Can be used in amounts of 0.1 to 10% by weight. As the adhesion imparting agent, conventionally known ones such as acrylic, amine, imine, etc. can be used. Furthermore, when stability of the sealer is required, Pb, Ba, Zn, etc. can be used as stabilizers.
Metal salts such as Sn, Ca, etc. and CaO, Al ₂ , O ₃ , CaCl ₂
Moisture absorbents such as can be used. The PVC sol sealer of the present invention has a flow property of 10 mm or less both horizontally and vertically at room temperature for 30 minutes, and a flow property of 50 mm or more horizontally at 110°C for 30 minutes.
It is 100mm or more vertically. In addition, flowability here is based on the flowability test of JIS K6830-13(2).
The test was conducted using a semicircular beat with a diameter of 10 mm. Both horizontal and vertical fluidity test methods measure the flow of sealer when a test plate to which a semicircular bead of sealer is attached is maintained vertically. And in the horizontal test, the semicircular beat of the sealer extends in the horizontal direction,
On the other hand, a vertical test refers to one in which the semicircular beat extends in the vertical direction. Thermal expansion of the PVC sol sealer of the present invention is 110℃10
50% or less in 140℃ for 30 minutes and 50% or more in 30 minutes at 140℃.
More preferably, the thermal expansion at 140°C for 30 minutes is 80%.
That's all. Note that the term "thermal expandability" here refers to the value obtained by dividing the volume increase from the volume before expansion by the volume before expansion, multiplied by 100. Therefore, thermal expansion of 50% means that the volume has become 1.5 times the original volume. The vinyl chloride sol sealer of the present invention can be obtained by blending the above-described base resin, temperature-sensitive thixotropic agent, thermally expandable particles, and other ingredients and kneading the mixture in a kneader or the like. Further, the flow characteristics and thermal expansion properties of the present invention can be easily adjusted by changing the types or amounts of the above-mentioned compounding materials. [Example] No. 1 shown in Table 1 as the PVC sol sealer of the present invention.
PVC sol sealers No. 1 to No. 4 were prepared. Here, the vinyl chloride resin used had a degree of polymerization of 1000 to 2000. Further, calcium carbonate was used as a filler, DOP was used as a plasticizer, and hydrogenated castor oil was used as a temperature-sensitive thixotropic agent. Tin was used as a stabilizer. Thermal expandable microcapsules having a particle size of 5 to 30 microns and containing isobutane as a volatile fluid were used. As comparative examples, two types shown in No. 11 and No. 12 were used. Each of these vinyl chloride sol sealers was obtained by individually kneading them in a kneader for 1.5 hours and then degassing them in the kneader for 2 hours. Next, each sealer obtained was subjected to a vertical fluidity test according to JIS K6830-13(2).

【table】

[Table] Natsuta. The results are also shown in the table. Also, to see the thermal expansion properties, 110℃, 120℃, 130℃ and 140℃
℃, the volumetric expansion coefficient when inserted at 110℃ for 8 minutes, the volumetric expansion coefficient when left at 120℃, 130℃ or 140℃ for 30 minutes,
The volumetric expansion coefficient was measured after being left at 110°C for 8 minutes and then at 140°C for 30 minutes.
The results are shown in Table 2. As is clear from Table 2, the vinyl chloride sol sealer of this example shows almost no flowability at room temperature, but begins to show flowability at temperatures above 110°C. Furthermore, this flowability does not become particularly large even at 140℃, and from 110℃ to
Shows almost the same flow performance between 140℃. The coefficient of volumetric expansion is less than 50% at 110℃ for 10 minutes, and more than 50% at 140℃ for 30 minutes or more. Below 110℃, the expansion rate is relatively small, and at a high temperature of 140℃, the expansion rate becomes large. On the other hand, comparative example No. 11 has almost the same fluidity as the example, but has no thermal expansion. Conversely, No. 12 is fluid at room temperature. Next, these PVC sol sealers were applied to the upper part of the slanted door hemming part of an automobile, and the performance of the PVC sol sealers was investigated using the heating during the body baking process. In addition, heating is for 10 minutes at 110℃ for primary baking.
The secondary baking time is 30 minutes at 140°C, and the tertiary baking time is 30 minutes at 140°C. The PVC sol sealers No. 1 to No. 4 of this example flowed into the gap in the door hemming part of the automobile during the primary baking,
It foamed and hardened during the secondary baking process, resulting in a reliable seal. On the other hand, Comparative Example No. 11 PVC sol sealer flowed well into the gap in the door hemming part, but some sealer was found to be insufficient in the wide part of the gap. In addition, the PVC sol sealer No. 12 began to flow even before baking, and it gathered in the low part of the gap in the door hemming area and expanded. This resulted in a lack of sealer in areas with high gaps.

Claims (1)

[Claims] 1. Average degree of polymerization when the whole is 100% by weight
500 to 3000% by weight of a base resin made of vinyl chloride resin or copolymer resin with vinyl chloride, and 0.1 to 10% of one or more temperature-sensitive thixotropic agents.
% by weight and 0.1-10% by weight of thermally expandable particles, at room temperature 30
The flow properties per minute are 10mm or less both horizontally and vertically, the flow properties are 50mm or more horizontally and 100mm or more vertically at 110℃ for 30 minutes, and the thermal expansion is 50mm or less at 110℃ for 10 minutes. % or less, and 50% or more at 140°C for 30 minutes. 2. The vinyl chloride sol sealer according to claim 1, which has a flow property of 50 mm or more horizontally and 100 mm or more vertically at 110°C for 30 minutes, and has a thermal expansion property of 80% or more at 140°C for 30 minutes.