JPS61296081A - Primer composition for tape - Google Patents

Abstract

PURPOSE:The titled primer composition which is laid between a substrate and a pressure-sensitive adhesive layer to improve adhesiveness and to prevent interface release, comprising halogenated butyl rubber, an organic polyisocyanate and an organic solvent as essential components. CONSTITUTION:The aimed composition comprising (A) halogenated butyl rubber (preferably containing <=50wt% regenerated butyl rubber and/or virgin butyl rubber), (B) an organic polyisocyanate and (C) an organic solvent as essential components, which forms a primer layer between a substrate and a pressure- sensitive adhesive layer of a tape consisting of the substrate of PE film or sheet and the pressure-sensitive adhesive layer of butyl rubber formed on the substrate. Preferably the amount of the component B is 3-150pts.wt. based on 100pts.wt. component A.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention provides a tape comprising a support made of a polyethylene film or sheet and a butyl rubber adhesive layer provided on the support. The present invention relates to an undercoat composition interposed between a support and the pressure-sensitive adhesive layer in order to improve the adhesion between the two.

[Prior Art] One method for preventing corrosion of pipes in oil and gas pipelines is an on-site wrapping method in which a bare steel pipe is wrapped with an adhesive anticorrosion tape having an adhesive layer provided on a support. The support for this anticorrosive tape is usually a polyethylene film or sheet that has excellent properties such as low-temperature properties, chemical stability, and economic efficiency, and the adhesive layer is usually a butyl rubber adhesive with low moisture permeability. is formed using

In general, the on-site winding method involves removing rust and dirt from the pipe surface, then applying a primer on top of this, wrapping an adhesive anti-corrosion tape called inner tape on top of this, and then wrapping a sampling tape around it. Completed.

By the way, the present inventor used a commercially available anti-corrosion tape (a polyethylene film or sheet support with a butylcom adhesive layer formed thereon), coated a steel plate with a primer, and then attached a sample body with the anti-corrosion tape on top of the primer. After storing it at room temperature for one month, according to ASTM D-1000,
Peeling 1 - When peeling resistance is measured using an autograph,
Figure 1A when the measurement temperature is 20℃, Figure 1B when the measurement temperature is 0℃, -
Figure 1 B is shown at 30°C, and Figure 1 is shown at -50°C. Also, when measuring the peel resistance, observing the state of destruction between the iron plate and the anticorrosive tape shows that the adhesive layer coagulates at 20°C. It peels off due to destruction, but at -30℃ and -
At 50°C, it was confirmed that the adhesive layer and the support were peeled off due to anchoring failure at the interface.

Generally, when a polyethylene film or sheet is used as a support, surface treatments such as chromic acid treatment and corona discharge treatment are usually applied to the surface of the support on which the adhesive layer is provided in order to improve adhesion. -30℃ or -5
At low temperatures around 0°C, it is not possible to reliably prevent the above-mentioned interfacial peeling.Especially when winding around steel pipes is performed using a mechanical winding method, the unwinding speed of the anti-corrosion tape is fast, so the above-mentioned interfacial peeling cannot occur. There was a drawback that this occurred.

[Purpose and Summary of the Invention] Therefore, the inventors have developed the anti-corrosion tape described in 1.
Improved adhesion between the support and the adhesive layer with the aim of preventing interfacial peeling when used at low temperatures of around 50°C and changing the fracture mode to the type shown in Figure 1 A. As a result of intensive study on 1 to 100% water-retaining undercoat, we have come to form this invention.

That is, the present invention provides a tape comprising a support made of a polyethylene film or sheet and a butyl rubber adhesive layer provided on the support, and an undercoat interposed between the support and the adhesive layer. The present invention relates to an undercoat composition for a tape, which is a composition for forming a coating layer, and which contains a halogenated butyl rubber, an organic polyisocyanate, and an organic solvent as essential components.

[Structure and operation of the invention]

The halogenated butyl rubber used in the tape primer composition useful for the anticorrosion tape of this invention includes ordinary chlorinated,
In addition to brominated and iodinated butyl rubbers, suitable amounts of recycled butyl rubber or virgin butyl can be used in combination, for example.

For example, the halogenated butyl rubber has a chlorine content of 1.0 to 1.4% by weight and a Mooney viscosity of ML1rs (
Chlorinated butyl rubber with a temperature of 45 to 55 (125°C), a bromine content of 1.8 to 2.4% by weight, and a Mooney viscosity of ML
Examples include brominated butyl rubber having a weight of 27 to 34 g (125° C.) and finely shaped butyl rubber.

Such halogenated butyl rubber is preferably used alone, but if necessary, recycled butyl rubber or virgin butyl rubber can be used in combination in an amount of 50% by weight or less, preferably 45% by weight or less. .

Next, as the organic polyisocyanate used in this invention, a compound having usually 2 to 3 isocyanate groups in the molecule is used, and specifically, triphenylmethane triisocyanate, tris(p-isocyanate phenyl) thio Phosphate, hexamethylene 1/6
-diisocyanates, etc.

The more the above organic polyisocyanate is added, the better results will be obtained in preventing interfacial peeling at low temperatures. However, when halogenated butyl rubber alone is used, it is possible to prevent interfacial peeling at low temperatures even when a relatively small amount is used. 5 halogenated butyl rubber
Even in a mixed system with recycled butyl rubber or virgin butyl rubber containing 0% by weight or more, the blending ratio of organic polyisocyanate is at least 0.8 parts by weight, preferably 1 to 200 parts by weight, per 100 parts by weight of halogenated butyl rubber. parts, practically ranging from 3 to 150 parts by weight.

Next, the organic solvent used in the present invention may be any solvent as long as it can dissolve the above-mentioned butyl rubber and organic polyisocyanate so as to uniformly disperse them, and examples thereof include toluene and xylene. The amount of this organic solvent used is usually 9 to 100 parts by weight per 1 part by weight of the total lid of the above-mentioned halogenated butyl rubber and organic polyisocyanate.
It is best to have heavy leaves.

The tape primer composition of the present invention contains each of the above-mentioned components as essential components, but may also contain a tackifying resin, an anti-aging agent, a pigment, a filler, a rust preventive agent, etc. as necessary. .

This undercoat composition is interposed between the support and the adhesive layer of an anticorrosion tape composed of a support made of a polyethylene film or sheet and a butyl rubber adhesive layer provided on the support. Although it is particularly useful as a primer layer, it can also be used to form the primer layer of other tapes.

To form this undercoat layer, it is sufficient to apply the above-mentioned undercoat composition on the above-mentioned polyethylene film or sheet and heat it for about 0.3 to 10 minutes, usually at 60 to 120°C. The organic solvent is removed and the composition is crosslinked to form a primer layer. The thickness of this undercoat layer is usually preferably about 0.01 to 10 μm. Note that the surface of the polyethylene film or sheet on which the undercoat layer is to be formed is subjected to known surface treatments such as corona discharge treatment and chromic acid treatment.

An adhesive anti-corrosion tape is obtained by forming a butyl rubber adhesive layer on the undercoat layer thus formed,
This anticorrosive tape is wound into a roll. The above-mentioned butyl rubber adhesive is a virgin 7'' iF rubber and/or recycled butyl rubber adhesive that is blended with a tackifying resin, filler, softener, crosslinking agent, etc. as necessary. However, the thickness of the butyl rubber adhesive layer formed using this adhesive is usually 30 ~
1. It is best to set it to about 500 μl.

The anticorrosion tape obtained as described above has an undercoat layer formed using the undercoat composition for anticorrosion tape of the present invention between the support made of polyethylene film or sheet and the butyl rubber adhesive layer. Since the adhesive layer is present therein, the adhesive property between the support and the pressure-sensitive adhesive layer is excellent.

For this reason, the anticorrosive tape wound into a roll is heated at low temperatures around -30°C or -50°C, usually at a rate of 1 to 30 pieces per coat.
Even when the adhesive layer is unwound and wound around a steel pipe at a speed of about 1 minute, the unwinding hardly causes peeling of the adhesive layer from the support, that is, so-called interfacial peeling.

This is because when the primer composition is applied onto a support made of polyethylene film or sheet, the composition penetrates into the fine cavities on the surface of the support, and then when heated, the composition penetrates into the fine cavities of the support. As the organic solvent evaporates, the organic polyisocyanate acts as a crosslinking agent and reacts with both the polar groups present on the surface of the support by surface treatment and the polar groups contained in the halogenated butyl rubber in the composition, forming a strong bond with the support. This is because a primer layer that adheres to the surface is formed.

〔Effect of the invention〕

As described above, since the primer composition of the present invention uses halogenated butyl rubber and organic polyisocyanate in combination with essential nonvolatile components, this combination allows for the formation of a support made of polyethylene film or sheet. It is composed of a butyl rubber adhesive layer provided on this support.
It functions effectively as a primer for anti-corrosion tape, and this type of tape wound into a roll can be coated at room temperature as well as at
Even when unwinding at a high temperature of 60°C or a low temperature of around -30°C or Vi-50°C, interfacial peeling in which the adhesive layer peels off from the support can be effectively prevented.

〔Example〕

Examples of this invention will be described below. In addition, in the following, parts mean parts by weight.

Examples 1 to 6 Brominated butyl rubber [odor-containing needles 2.1% by weight, Mooney viscosity ML 1+8 (125°C) 31], organic polyisocyanate [tris(p-isocyanate phenyl) thiophosphate] and toluene were mixed as follows. Formulation 1-1 An undercoat composition for tape according to the present invention was obtained in the proportions shown in Table 1.

On the other hand, high density polyethylene (density 0.960, melt index 0.12) and low density polyethylene (density 0.
92o, melt index 0.35') and 20:8
They were melt-mixed at a ratio of 0 (weight ratio) and extruded through a T-die to obtain a polyethylene film with a thickness of 0.38111. Next, one side of this film was subjected to corona discharge treatment.

In addition, 100 parts of butyl rubber was added to Nigu, and then 5 parts of carbon black and 1 part of polyisobutylene rubber were added.
0 parts of polyterpene resin, 40 parts of polybutene, 60 parts of light calcium carbonate, and 2 parts of anti-aging agent 1F were mixed and kneaded for 20 minutes to prepare a butyl rubber adhesive.

The above primer coating composition for tape is applied to the corona discharge treated surface of the above polyethylene film at 1 to 80°C.
It was heated for 1 minute to form a 0.5 μm thick grooved primer layer. The above-mentioned butyl rubber adhesive was applied to this undercoat layer-F using a calendar roll or an extruder to form a butyl rubber adhesive layer with a thickness of 0.251 m, thereby producing an anticorrosive tape. This anti-corrosion tape is wound into a roll around a ball core.
This was cut into a width of 25111 mm to obtain a roll of anticorrosion tape.

Next, the anchoring force of this tape between the tape support and the adhesive at low temperature was evaluated as follows.

That is, prepare a 15011 square iron plate with a thickness of 3 mm, polish the surface of this iron plate with a #280 sandblade, and apply the butyl rubber adhesive on the polished surface with a base treatment agent and the above-mentioned butyl rubber adhesive. Treatment with a 20% by weight hexane solution 1-1 The above-mentioned anticorrosive tape was pasted on the treated surface, a load of 10 g/d was applied thereon, and a sample body was prepared which was stored at room temperature for 4 weeks.

Next, this sample body was heated to 0°C, -30°C, and -50°C for 4 hours, respectively.
After storage for a period of time, the anchoring force between the tape support and the adhesive layer and the state of destruction at the interface were measured according to the ASTM D-1000 measurement method. The results are shown in Table 1.

In addition, the codes of AlB, C and D indicating the fracture state at the interface in Table 1 indicate the fracture modes shown in Figure 1 A, B%C and D, respectively, and the numbers on the codes of C and D indicates the maximum value at the time of destruction.

Table 1 Examples 7 to 12 Chlorinated butyl rubber as halogenated butyl rubber (chlorine content 1.2% by weight, Mooney viscosity ML!+5 (125°C
) 50) was used, anticorrosion tapes were made in the same manner as in Examples 1 to 6, and the anchoring force was measured. The results are shown in Table 2.

Table 2 As is clear from the above Examples and Comparative Examples, butyl rubber-based adhesives are coated on a support made of polyethylene film or sheet through an undercoat layer formed using the undercoat composition for tapes of the present invention. The adhesive anti-corrosion tape provided with an adhesive layer has good adhesion between the support and the adhesive layer, and the adhesive layer can be supported even at low temperatures around 0°C, -30°C and -50°C. The fact that peeling from the body, so-called interfacial peeling, is difficult to occur is remarkable.

[Brief explanation of drawings]

Figure 1 A%B, C and D are 20℃, 0℃, -30℃ respectively
and peeling at -50°C 1. It is a chart of peeling resistance.

Claims (3)

[Claims] (1) In a tape composed of a support made of a polyethylene film or sheet and a butyl rubber adhesive layer provided on the support, an undercoat layer is interposed between the support and the adhesive layer. 1. An undercoat composition for tape, which is a composition for forming a tape, and contains a halogenated butyl rubber, an organic polyisocyanate, and an organic solvent as essential components. (2) The halogenated butyl rubber contains 50% by weight or less of recycled butyl rubber and/or virgin butyl rubber, and the blending ratio of the organic polyisocyanate to 100 parts by weight of the halogenated butyl rubber is at least 0.8 parts by weight. The tape primer composition described in (1). (3) The tape primer composition according to claim (2), wherein the organic polyisocyanate is blended in an amount of 0.8 to 200 parts by weight per 100 parts by weight of halogenated butyl rubber.