JPH09235513A - Primer composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a primer composition, comprising specific two kinds of prepolymers, capable of being thinly coated at an ambient temperature in spite of a solventless system, having quick initial curability, hardly changing the viscosity at the time of storage and excellent in film-forming properties and adhesion to a hardly bondable material. SOLUTION: This primer composition comprises (A) a prepolymer composed of a polyether polyol having <1000 number-average molecular weight (preferably dipropylene glycol) and a liquid modified diphenylmethane diisocyanate (hereinafter referred to as MDI) (preferably a carbodiimide-modified MDI having 15-30% carbodiimide content) and (B) a prepolymer composed of a hydroxyl- terminated polybutadiene having 1000-3000 number-average molecular weight (preferably the one containing >=50wt.% 1,4-adduct) and/or a polyether polyol, compatible therewith and having 200-3000 number-average molecular weight (preferably polybutylene glycol), the MDI and/or hexamethylene diisocyanate. A curing catalyst or a latent curing agent or both may be blended in the objective composition.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a non-adhesive coated plate which can be applied at room temperature even though it is a solvent-free system, has a low viscosity at the time of application, is excellent in initial curing property and film-forming property and adhesive property to the non-adhesive coated plate. The present invention relates to a primer composition having excellent adhesiveness with a sealing agent.

[0002]

2. Description of the Related Art Conventionally, a wind sealant has been used to bond an automobile body to a window glass. But,
Since the adhesiveness is not sufficient, in order to improve the adhesiveness, a glass primer is pre-applied between the window glass and the wind sealant, and the viscosity including the organic solvent is about 70% between the body and the wind sealant. A coating surface primer composed of a urethane prepolymer of 10 to several hundred cps, a thermoplastic resin, and a tackifier is applied in advance.

However, since solvent-based urethane resins cause environmental pollution due to discharged solvents and the like, the development of primers that do not use solvents is being promoted. Further, the body of an automobile is coated with a hard-adhesive paint such as a high solid type metallic top coating. Therefore, showing excellent adhesion between the hard-to-adhere coated plate and the wind sealant, the initial hardness development time when applied to the hard-to-adhesive coated plate, that is,
There is a demand for a primer for a surface of a wind sealant, which requires a short time for the wind sealant to have a hardness after application as a primer, has a hardness that can be applied thinly to a coating plate having poor adhesion, and has storage stability.

An adhesive using a urethane prepolymer is a reactive hot melt adhesive composition obtained by adding a thermoplastic resin and an adhesion-imparting material to a urethane prepolymer composed of butanediol and diphenylmethane diisocyanate (hereinafter abbreviated as MDI). And urethane prepolymers using mixed polyols composed of polyester polyols and polyether polyols have been reported. However, in the conventional hot melt adhesive, the urethane resin that has been heated and melted has high adhesiveness to the adherend, but it does not show excellent adhesiveness to a wide range of adhesive materials, and the coating thickness is still thick. It has the drawback of uneven coating.

In order to solve the above problems, therefore, a hydroxyl group-terminated polybutadiene (hereinafter abbreviated as 1,2-PBD) containing a polyether polyol, a polyester polyol, and a 1,2-adduct as main components. A urethane resin composition composed of a mixed polyol consisting of a polyisocyanate and a polyisocyanate has been proposed (Japanese Patent Laid-Open Publication No. Hei 7 (1999) -107242).
-173245, JP-A-7-173246). Hitherto, the compatibility of the polyol species and the isocyanate species contained in the urethane resin has been considered important for obtaining good adhesiveness. The above-mentioned urethane resin composition is also considered so that the contained prepolymer is highly compatible. This is because when the phase compatibility is poor and the phases are separated, the adhesiveness is reduced and the offsetting effect is exhibited as compared with the prepolymer synthesized by using polyester polyol and polybutadiene glycol alone as the polyol component. is there. Therefore, the polyether polyol contained in the above-mentioned urethane resin composition has a number average molecular weight of 1 so as to be highly compatible with other prepolymers.
It is limited to the range of 000 to 10,000. Also, since the polyether polyol acts as a compatibilizer,
The polybutadiene glycol contained in the urethane resin composition has improved compatibility regardless of whether it is 1,4-PBD or 1,2-PBD. Adhesion should be good regardless of which is used. However, 1,4-PBD has poor adhesion to all test materials, and it is assumed that 1,2-PBD exhibits excellent adhesion, and 50% by weight of 1,2-PBD is used.
It is preferable to include the above. By selecting the conditions as described above, high adhesiveness is obtained at room temperature for a wide variety of plastics from polar polymers to non-polar polymers. However, the viscosity of the urethane resin composition at room temperature is still as high as over 20000 cps, and there is a problem that it cannot be applied thinly.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is to solve the above-mentioned problems of the primer composition, to have a low melt viscosity at room temperature even though it is solvent-free, and to be applied thinly to an adherend,
(EN) It is intended to provide a solventless primer composition which has a short initial curing expression time and is excellent in adhesion between a difficult-to-adhere coating plate and a sealant agent.

[0007]

DISCLOSURE OF THE INVENTION The present inventors have found that a first prepolymer consisting of a low molecular weight polyether polyol and a MDI liquid modified product is compatible with a hydroxyl-terminated polybutadiene and / or a hydroxyl-terminated polybutadiene. A primer composition composed of a second prepolymer composed of a polyether polyol and a polyisocyanate can improve the above-mentioned drawbacks of the prior art, and is a solvent-free system and can be applied thinly at room temperature. A primer composition that can be used, has a fast initial curability, can maintain the adhesiveness after application for a long time of several hours, has good film-forming properties and adhesiveness on a difficult-to-adhere coating plate, and has a small viscosity change during storage in a container. The present invention has been completed and the present invention has been completed.

That is, a first prepolymer consisting of a polyether polyol having a number average molecular weight of less than 1000 and a MDI liquid modified product; a hydroxyl group-terminated polybutadiene having a number average molecular weight of 1000 to 3000 and / or a number compatible with the hydroxyl group terminated polybutadiene. Polyether polyol having an average molecular weight of 200 to 3000, p-MDI (indicated in MDI containing only a monomer of pure MDI, hereinafter referred to as pure MDI) and / or hexamethylene diisocyanate (hereinafter referred to as HDI). And a second prepolymer consisting of 2).

There is provided a primer composition in which the polyether polyol contained in the first prepolymer has a number average molecular weight of 72 to 400.

A primer composition is provided wherein the MDI liquid modification contained in the first prepolymer is a carbodiimide modified diphenylmethane diisocyanate.

There is provided a primer composition in which 50% by weight or more of hydroxyl-terminated polybutadiene contained in the second prepolymer is 1,4-bonded polybutadiene glycol.

The polyether polyol contained in the first prepolymer is dipropylene glycol and the second
The polyether polyol contained in the prepolymer of
Provided is a primer composition that is polybutylene glycol.

The NCO / OH ratio between the polyether polyol and the polyisocyanate is 1.0 to 18.0, and the NCO / OH ratio between the hydroxyl-terminated polybutadiene and the polyisocyanate is 4.0 to 8. At least 1 of a second prepolymer having a NCO / OH ratio of 4.0 to 8.0 of a second prepolymer having a pH of 0.0 or a polyisocyanate compatible with a hydroxyl-terminated polybutadiene.
There is provided a primer composition containing a seed.

The above-mentioned primer composition provides a primer composition containing 0.01 to 5.0 parts by weight of a tin-based catalyst or a latent curing agent, respectively.

Further, 0.8 to 3.0 parts by weight of a film stabilizing agent,
And a primer composition containing 5.0 to 20 parts by weight of carbon black.

Hereinafter, the present invention will be described in detail. The solventless primer composition of the present invention comprises a first prepolymer composed of a polyether polyol having a low molecular weight and an MDI liquid modified product, and a hydroxyl group-terminated polybutadiene and / or a polyether polyol having a relatively high molecular weight and a polyisocyanate. It is characterized by mixing the following second prepolymer. Here, as the second prepolymer, each of the following (2-1) or (2-2) prepolymers may be mixed alone with the first prepolymer,
Both the (2-1) and (2-2) prepolymers may be mixed with the first prepolymer. (2-1): Hydroxyl group-terminated polybutadiene having a number average molecular weight of 1000 to 3000 and p-MDI and / or HDI
Prepolymer containing (2-2): A prepolymer containing a polyether polyol having a number average molecular weight of 200 to 3000 and p-MDI and / or HDI.

The first prepolymer is obtained by reacting a polyether polyol with an MDI liquid modified product. The polyether polyol has a number average molecular weight of less than 1000, preferably 72 to 400, more preferably 100 to
At 250, for example, a compound having a skeleton obtained by addition-polymerizing one or more alkylene oxides such as ethylene oxide, propylene oxide and butylene oxide with a compound having two or more active hydrogens. Alternatively, it is a compound having two hydroxyl groups at the molecular end by ring-opening polymerization of tetrahydrofuran or the like. When the number average molecular weight is less than 1000, the viscosity of the obtained primer composition is 800 to 10,000 cp at room temperature.
s, which is sufficiently low. Here, examples of the compound having two or more active hydrogens include polyhydric alcohols, amines, alkanolamines, and polyhydric phenols. Polyhydric alcohols include ethylene glycol, propylene glycol, butanediol, diethylene glycol, glycerin, hexanetriol, pentaerythritol, and the like, and amines include ethylenediamine, hexamethylenediamine, polyoxypropylene-polyamine, and alkanolamines. Are propanolamine, N, N'-bis-
Examples of polyphenols such as 2-hydroxypropylaniline include resorcin, bisphenol A, and propylene oxide adduct of bisphenol A. Specifically, polytetramethylene ether glycol (PTMG), polyoxypropylene glycol (P
PG) and polyethylene glycol (PEG), but more preferably dipropylene glycol (DP).
G).

An MDI liquid modified product can be used as the isocyanate used in the first prepolymer of the present invention. Examples of the MDI liquid modified product include c-MDI and carbodiimide modified MDI. c-MDI is a mixture of a pure MDI monomer and a polymer obtained by polymerizing the monomer,
For example, diamino-which is a condensate of aniline and formalin
It can be obtained by phosgenation of diphenylmethane. c-MDI includes polymeric MDI, 4,
Examples thereof include MDI isomers such as 4'-MDI, 2,4'-MDI, and 2,2'-MDI, or a mixture thereof. Also included are modified MDIs that are liquefied by reacting pure-MDI with low molecular weight glycols such as ethylene glycol and propylene glycol, or long-chain polyols.

A carbodiimide-modified MDI can also be preferably used. The carbodiimide-modified MDI is a compound in which the isocyanate group of MDI is decarboxylated and bound through the carbodiimide group, and includes, for example, modified MDI obtained by heating pure-MDI to dimerize it and carbodiimidating it. This reaction can be carried out at a high temperature without a catalyst, but is promoted by the catalyst even at a room temperature. The amount of carbodiimide in all the modified products is 1
5-30% is preferred. The reason for setting this range is that by-products are not formed in this range and the liquid is low in viscosity.

The first prepolymer is the ratio of NCO groups in the MDI liquid modified product to OH groups in the polyol (NCO /
OH ratio) is 10.0 to 18.0, preferably 12.0 to
It is preferable that the reaction is carried out so as to be 16.0. NCO
NCO / OH of the second prepolymer whose / OH ratio is described later
It is larger than the ratio (4.0 to 8.0, etc.), and the range is set so that the adhesiveness of the urethane prepolymer does not come out when 10.0 or less, and the free isocyanate is large and the curability and the like are high when 18.0 or more. This is because the reactivity is affected, and in addition, the effect of lowering the viscosity can be expected.

The hydrogen-terminated polybutadiene used in the second prepolymer of the present invention can be obtained by radical polymerization of butadiene, which is heated under pressure with oxygen and a small amount of an initiator such as peroxide. Can be done by. Hydrogen-terminated polybutadiene is 1,2-P
It may contain either BD or 1,4-PBD,
It is more preferable to use a hydrogen-terminated polybutadiene containing 1,4 adduct in a larger amount than 1,2 adduct, that is, 1,4-PBD in an amount of 50% or more. For example, a structure represented by the following structural formula 1, that is, a structure in which cis type, vinyl type, and trans type are mixed in a ratio of 0.2: 0.2: 0.6 can be preferably used. Specifically, R-15HT (1,4-made by Idemitsu Petrochemical Co., Ltd.)
80% PBD content, R-45HT (1,4-P
A BD content rate of 80%) or the like can be used.

Structural formula 1

Embedded image

The number average molecular weight of the hydrogen group-terminated polybutadiene contained in the second prepolymer is preferably 1000.
-3000, more preferably 1500-2800. The reason why the number average molecular weight of the hydroxyl group-terminated polybutadiene is within the above range is that the coating film becomes brittle when the number average molecular weight is less than this range, and the viscosity becomes high when the number average molecular weight exceeds the above range. Because.

Pure MDI and hexamethylene diisocyanate are preferably used as the polyisocyanate contained in the second prepolymer.

For the second prepolymer, a polyether polyol compatible with the hydroxyl group-terminated polybutadiene can be used together with the above-mentioned hydroxyl group-terminated polybutadiene, or in place of this. Examples of compatible polyether polyols include aromatic amine-based compounds and phenol-based compounds, but polybutylene glycol is particularly preferably used. Specifically, Kikosanol 500 and PBG-3000 manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd. can be used. The number average molecular weight of such a polyether polyol is preferably 200 to 3000, more preferably 40.
0 to 1000. If the molecular weight of the polyether polyol is lower than the above range, the coating film becomes brittle, and if it is higher than the above range, the viscosity becomes high.

When a hydroxyl-terminated polybutadiene is used as the second prepolymer, the ratio of NCO groups of polyisocyanate to OH groups of hydroxyl-terminated polybutadiene, NCO / O.
It is preferable that the H ratio is 4.0 to 8.0, preferably 5.0 to 7.0. The reason why the above NCO / OH ratio is in this range and free isocyanate is present is that the effect of lowering the viscosity can be expected.

The second prepolymer is obtained by reacting a polyether polyol having compatibility with the hydroxyl group-terminated polybutadiene with a polyisocyanate consisting of pure MDI or HDI, or a mixture thereof, in place of the above-mentioned hydroxyl group-terminated polybutadiene. Can also be obtained. During the reaction, the NCO / OH ratio of the NCO groups of the polyisocyanate and the OH groups of the polyether polyol compatible with the hydroxyl-terminated polybutadiene is 4.0 to 8.0, preferably 5.0 to 6. It is preferably 0. Above NCO / OH
The ratio is set in this range because the viscosity is low.

The hydroxyl-terminated polybutadiene and the polyether polyol compatible with the hydroxyl-terminated polybutadiene may be reacted with the polyisocyanate alone, or may be used as a mixture.

The primer composition of the present invention comprises the first prepolymer and the second prepolymer,
As a compounding ratio of the first prepolymer and the second prepolymer at the time of charging, the ratio of the first prepolymer and the second prepolymer is preferably 20:80 to 80: 2.
0, more preferably 30:70 to 50:50.
When the amount of the first prepolymer is less than 20 parts by weight, the viscosity of the obtained composition becomes high and the adhesiveness cannot be obtained, and when the amount of the second prepolymer is less than 20 parts by weight, the above range is set. This is because good curability and adhesiveness cannot be obtained. When the second prepolymer contains both a hydroxyl group-terminated polybutadiene and a polyether polyol compatible with the second prepolymer, the ratio of the hydroxyl group-terminated polybutadiene and the polyether polyol is 30:70 to 70:30, preferably 45:55. It is preferably set to 55:45. This is because when the content of the hydroxyl group-terminated polybutadiene is large, the time required to reach the hardness at which the sealant agent can be applied after the application of the primer composition is shortened, but when the content of the polyether polyol is large, the viscosity becomes low. The above range is preferable in order to balance the effects of both.

The primer composition of the present invention may contain a curing catalyst. Also, a latent curing agent may be added. The curing catalyst or latent curing agent may be contained alone, or both may be contained. When these are contained, the initial curability is further accelerated. The curing catalyst used in the present invention is dioctyltin dilaurate (DO).
TL), dibutyltin dilaurate, dibutyltin diacetate, dibutyltin mercuride, and other tin-based catalysts. As the latent curing agent used in the present invention, N-hydroxyethyl-2-isopentyloxazolidine and its xylylene diocyanate (XD
I) Adducts and other oxazolidines can be mentioned. The addition amount of the curing catalyst and the latent curing agent is the first
And 0.01 to 5.0 parts by weight, and more preferably 0.0 to 5.0 parts by weight, based on 100 parts by weight of the second prepolymer.
1 to 0.2 parts by weight may be added. The range is defined as
Within this range, the storage stability of the primer composition intended by the present invention is not affected, and the initial curing is shortened to 30 minutes or less while the storage stability remains stable.

Furthermore, the primer composition of the present invention preferably contains 0.8 to 3.0 parts by weight, more preferably 1.0 to 1.5 parts by weight of a film stabilizer and carbon black preferably of 5. 0 to 20 parts by weight, more preferably 10 to 15
You may include a weight part. Within this range, the film-forming effect can be obtained without increasing the viscosity, and the adhesiveness can be improved.
The time required for applying the sealant after applying the primer composition is shortened.

Further, the primer composition of the present invention may contain various stabilizers, plasticizers, tackifiers, fillers and the like, in addition to the tin catalyst and the latent curing agent.

The stabilizer is a silane coupling agent or the like, the plasticizer is a phthalic acid ester, an aliphatic dibasic acid ester, a glycol ester or the like, and the tackifier is a rosin or its derivative, a terpene resin or the like. Examples of the natural resin, petroleum resin, hydrogenated petroleum resin, and the like include carbon black, calcium carbonate, barium sulfate, talc, clay, and titanium oxide.

The first and second prepolymers are prepared by a one-shot method in which a mixed polyol and an isocyanate are separately prepared and uniformly mixed, or a prepolymer in which the polyol and the isocyanate are used as respective prepolymers and then mixed. It may be manufactured by any method. At this time, if necessary, other additives may be added for production. The one-shot method is advantageous in that it is simple and inexpensive, and the prepolymer method is expected to exhibit stable coating film properties.

The composition thus produced can be used as a primer for the wind sealant and the hard-to-adhere coated plate. The wind sealant adheres the body of the automobile to the window glass, and a commonly used polyurethane sealant can be used, and specific examples thereof include commercially available products such as WS-70 manufactured by Yokohama Rubber Co., Ltd. Examples of the hard-to-adhere coated plate include a coated plate used for an automobile body and the like, for example, an acrylic melamine-based coated plate used for an electrodeposition coated steel plate and the like. As a method of applying the composition of the present invention, it can be applied at room temperature, after applying the composition of the present invention to a difficult-to-adhesive coated plate, it is solidified to form a film for a wind sealant having a sufficient initial adhesive strength. Once the film has been formed, a wind sealant can be applied onto it, and the glass and wind sealant can be brought into close contact with each other and adhered.

In the primer composition of the present invention, the first prepolymer having a low molecular weight and the second prepolymer having a relatively high molecular weight are mixed with each other, but they are partially compatible but almost separated.
Therefore, when the content ratios of the hydroxyl-terminated polybutadiene and the polyether polyol are significantly different, it is necessary to stir to some extent when applying the primer composition. Further, since the primer composition is phase-separated, when the primer composition of the present invention is applied to a difficult-adhesion coated plate, the first prepolymer is present on the difficult-adhesion coated plate side and the second prepolymer on the wind sealant side. Prepolymer is now present,
It is considered that the hard-to-adhere coated plate and the wind sealant are bonded to each other via the primer composition of the present invention.

The composition of the present invention is particularly useful as a primer for adhering a difficult-adhesion coated plate such as an acrylic melamine-based coated plate to a wind sealant. In addition to this, it can also be used as a primer for adhering a sealant with an adhesive so as to prevent water from entering the movable window or trunk of an automobile from the outside.

[0038]

EXAMPLES The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples. In the examples, the following prepolymers were produced and blended to produce a primer composition, and its physical properties were evaluated. The abbreviated names refer to the following substances. DPG: dipropylene glycol PBG: polybutylene glycol PPG: polyoxypropylene glycol 1,4-BD: butadiene 1,4 adduct TPG: tripropylene glycol PCL: polycaprolactone polyol prepolymer 1: polyether polyol (number average molecular weight 134 ) And carbodiimide modified liquid MDI to NCO /
Primer produced with an OH ratio of 17.0. Prepolymer 2: R-45HT (having a number average molecular weight of 280
0, 1,4-PBD content 80%) and p-MDI
Primer produced with a CO / OH ratio of 7.0. Prepolymer 3: R-15HT (having a number average molecular weight of 150
0, 1,4-PBD content 80%) and p-MDI
Primer produced with a CO / OH ratio of 7.0. Prepolymer 4: PBG (number average molecular weight 500) and HD
Primer prepared with I NCO / OH ratio 4.0. Prepolymer 5: PPG (number average molecular weight 1000) and c
-A primer made of MDI with an NCO / OH ratio of 6.0. Prepolymer 6: 1,4-BD (molecular weight 90) and c-M
A primer made of DI with an NCO / OH ratio of 6.0. Prepolymer 7: TPG (number average molecular weight 192) and c-
A primer made of MDI with an NCO / OH ratio of 7.0. Prepolymer 8: PCL (number average molecular weight 550) and c
-A primer made of MDI with an NCO / OH ratio of 7.0. Prepolymer 9: R-45HT (number average molecular weight 280
0) and p-MDI with an NCO / OH ratio of 2.0. Prepolymer 10: 1,2-PBD (number average molecular weight 18
Content of 50,1,2-PBG 85%, Nippon Soda Co., Ltd.
NISSO-PB GI-2000) and p-MDI
With an NCO / OH ratio of 7.0.

The following physical properties were evaluated for the examples described below. [1] Viscosity: The viscosity of the manufactured primer composition at room temperature was measured. [2] Open time A: A coated plate obtained by baking a primer composition with a high solid metallic topcoat (800
After 6), it is placed under the condition of 20 ° C. and 65% RH, and the wind sealant (WS-7 manufactured by Yokohama Rubber Co., Ltd.)
The time until the primer composition was solidified to a hardness at which 0) could be applied was defined as open time A, and this was measured. [3] Open time B: After applying the primer composition,
It was left in an environment of 35 ° C. and 95% RH, and the time for which the development of the adhesiveness with the wind sealant (WS-70) was maintained was measured. [4] Adhesiveness: A primer composition was applied, and after curing, a wind sealant (WS-70) was applied in a thickness of 3 mm, and the adhesiveness was examined under the following conditions. Initial Adhesion Property It was peeled by hand after standing for 7 days under the conditions of 20 ° C. and 65% RH. Resistance to hot water adhesion After standing for 3 days under the conditions of 20 ° C. and 65% RH, it was left standing in water of 40 ° C. for 10 days, and then peeled by hand. In the adhesiveness evaluation, ⊚ indicates that the breakage of the wind sealant was 95% or more of the bonded portion. ○ indicates that the breakage of the wind sealant was 80% or more of the bonded portion. × indicates that the breakage of the wind sealant was less than 80% of the bonded portion.

(Example 1) Prepolymer 1 and prepolymer 2 were mixed in an amount of 70:30 parts by weight to prepare a catalyst DOTL.
0.16 parts by weight and 12 parts by weight of carbon black were added and melt-blended to prepare a primer composition. (Example 2) Prepolymer 1 and Prepolymer 2 30:
The same procedure as in Example 1 was carried out except that the amount was 70 parts by weight. (Example 3) Prepolymer 1 and prepolymer 3 were 70:
The same procedure as in Example 1 was carried out except that the amount was 30 parts by weight. (Example 4) Prepolymer 1 and prepolymer 3 were 30:
The same procedure as in Example 1 was carried out except that the amount was 70 parts by weight. (Comparative Example 1) Prepolymer 1 and prepolymer 10 were 3
The same procedure as in Example 1 was carried out except that the compounding amount was 0:70 parts by weight. (Comparative Example 2) Prepolymer 2 and prepolymer 5 were 30:
The same procedure as in Example 1 was carried out except that the amount was 70 parts by weight. Comparative Example 3 The procedure of Example 1 was repeated except that 100 parts by weight of Prepolymer 2 was used. (Comparative Example 4) Prepolymer 1 and Prepolymer 9 were 30:
The same procedure as in Example 1 was carried out except that the amount was 70 parts by weight.

Next, a primer composition consisting of two or three prepolymers of the present invention was produced, and its physical properties were evaluated for Examples 5-8 and Comparative Examples 5-7. Example 5 Prepolymers 1, 3 and 4 were added to 63:
The same procedure as in Example 1 was carried out except that the compounding amount was 27:10 parts by weight. Example 6 Prepolymers 1, 3 and 4 in 56: 2
The same procedure as in Example 1 was carried out except that the compounding amount was 4:20 parts by weight. Example 7 Prepolymers 1, 3 and 4 at 24: 5
Same as Example 1 except that 6:20 parts by weight was blended. (Example 8) Prepolymer 1 and prepolymer 4 were 70:
The same procedure as in Example 1 was carried out except that the amount was 30 parts by weight. (Comparative Example 5) Prepolymer 4 and Prepolymer 5 were 30:
The same procedure as in Example 1 was carried out except that the amount was 70 parts by weight. (Comparative Example 6) Prepolymer 6 and Prepolymer 7 were 70:
The same procedure as in Example 1 was carried out except that the amount was 30 parts by weight. (Comparative Example 7) Prepolymer 6 and Prepolymer 8 were 70:
The same procedure as in Example 1 was carried out except that the amount was 30 parts by weight.

The results are shown in the table.

[Table 1]

[0043]

[Table 2]

As shown in Examples and Comparative Examples, when the number average molecular weight of the polyether polyol contained in the first prepolymer is large, the adhesiveness becomes low. Also, the first
If it does not contain any of the prepolymers, the adhesiveness with the sealant will be low. That is, it can be seen that the polyether polyol having a small number average molecular weight effectively acts on the adhesion to the hard-to-adhere coated plate, but is not so effective on the adhesion to the sealant agent. Insufficient polyisocyanate present in the prepolymer results in high viscosity. When the number average molecular weight of the hydroxyl group-terminated polybutadiene is small, the viscosity is high, and therefore the open time B (the time for which the development of adhesiveness is maintained) is short and the adhesiveness is also reduced.

[0045]

As described above, according to the present invention, a urethane prepolymer composed of a polyether polyol having a small number average molecular weight and c-MDI, a polyether polyol having a compatibility with hydrogen group-terminated polybutadiene or a hydroxyl group polybutadiene, and a polyether polyol. By appropriately selecting the polyol type, its number average molecular weight, and the blending ratio, the urethane prepolymer made of isocyanate can be applied at room temperature, and the viscosity at the time of coating is as low as 800 to 10,000 cps, and therefore the coating thickness is You can't see the uneven application
The initial hardness development time is as short as 30 minutes or less and it can be quickly transferred to the next step, the open time is long, the film-forming property on the difficult-to-adhesive coating plate and the adhesive property especially against hot water are good, and it is stored in the container. It is possible to obtain a stable primer composition with a small change in viscosity during the operation. Therefore, the primer composition of the present invention imparts excellent adhesion between the poorly-adhesive base material and the sealing material, thereby obtaining a primer composition that can be suitably used as a solvent-free primer for difficult-to-adhere coated plates. be able to.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C09D 175/14 PHR C09D 175/14 PHR PHV PHV

Claims (8)

[Claims] 1. A primer composition containing the following first and second prepolymers: First prepolymer: containing a polyether polyol having a number average molecular weight of less than 1000 and a liquid modified product of diphenylmethane diisocyanate. 2nd prepolymer: number average molecular weight 1000 to 3000
Number-average molecular weight compatible with the hydroxyl-terminated polybutadiene and / or the hydroxyl-terminated polybutadiene of 200 to 3
Prepolymer containing 000 polyether polyols and diphenylmethane diisocyanate and / or hexamethylene diisocyanate. 2. The primer composition according to claim 1, wherein the polyether polyol contained in the first prepolymer has a number average molecular weight of 72 to 400. 3. The primer composition according to claim 1, wherein the liquid modified product of diphenylmethane diisocyanate contained in the first prepolymer is carbodiimide modified diphenylmethane diisocyanate. 4. The primer composition according to claim 1, wherein 50% by weight or more of hydroxyl-terminated polybutadiene contained in the second prepolymer is 1,4-bonded polybutadiene glycol. 5. The polyether polyol contained in the first prepolymer is dipropylene glycol, and the polyether polyol contained in the second prepolymer is polybutylene glycol. A primer composition according to item 1. 6. The ratio of the NCO group of the isocyanate component and the OH group of the polyol component and the NCO / OH ratio contained in the first and second prepolymers are within the following ranges. Primer composition described in 1): First prepolymer; 10.0 to 18.0 Second prepolymer; Ratio of hydroxyl group-terminated polybutadiene contained as polyol component to isocyanate
4.0-8.0 Ratio of polyether polyol and isocyanate that are compatible with hydroxyl group-terminated polybutadiene contained as a polyol component 4.0-8.0 7. The primer composition according to claim 1, further comprising 0.01 to 5.0 parts by weight of a tin-based catalyst or a latent curing agent, respectively. 8. Further, 0.8 to 3.0 parts by weight of a film stabilizing agent,
The primer composition according to any one of claims 1 to 7, containing 5.0 to 20 parts by weight of carbon black.