KR20070019560A - Primer composition - Google Patents

Abstract

The present invention is made from a mixture of at least one polyisocyanate (B) of formula (I) and an amorphous polyester resin (A) comprising at least one OH group and solid at room temperature and comprising at least one binder comprising an isocyanate group It relates to a primer composition comprising a. The solid polyester resin (A) and polyisocyanate (B) have a stoichiometric ratio of NCO groups to OH groups in the range of 50: 1 to 100: 1 and / or polyester resins to polyisocyanates (B) The weight ratio of (A) has a value between 1.6 and 0.75, in particular between 1.2 and 0.8.

The primer composition of the present invention has the significant advantage of effective adhesion to plastic paints, in particular automotive paints.

Primer composition

Description

Primer composition {PRIMER COMPOSITION}

The present invention relates to a primer composition.

Adhesive bonding is a widely used bonding technique. Due to the many substrates possible to be bonded to each other, there are cases where the spacing between the substrates cannot be applied with an adhesive or a sufficient adhesive can be applied. Special primers have already been used for a long time to facilitate the bonding of the sealing material and the adhesive to such substrates.

Plastics and painted substrates are very important substrates in the industry. Due to the variety of paints, the surfaces of painted substrates are known to be difficult to bond. Of particular importance is a new generation of automotive coatings that combine with a one-component polyurethane adhesive or sealant.

Efforts have been made to develop pretreatment methods to increase the adhesion to paint. In particular, US 4,857,366 discloses undercoats for pates containing p-toluenesulfonic acid, and WO-A-99 / 31191 is directed to aromatic or alkyl aromatic solvents to enhance adhesion to paints. Or solutions of hydrocarbyl-substituted aromatic sulfonic acids in alkyl alcohols.

On the other hand, A 2004/033519 discloses a primer composition containing a catalyst system and a polyurethane prepolymer obtainable from aromatic nitrogen compounds and bismuth compounds, which greatly improves adhesion to paint. US-A-2003 / 0084995 discloses primer compositions comprising solvents, catalysts, polyisocyanates and resins. Possible ranges of substrates are referred to as resins and polyisocyanates. Such compositions are disclosed that can be used as primers for plastics such as PVC, polyurethane, polyolefins, polystyrenes, EPDM.

It is an object of the present invention to provide new primers which greatly enhance the adhesion of polyurethane adhesives and sealants to paints and plastics, in particular to paints.

The primer composition of the present invention according to claim 1 was found to greatly improve the adhesion of the polyurethane adhesive to paint and plastic.

The primer composition of the present invention includes a binder containing an isocyanate group.

The binder is made from a mixture of amorphous polyester resin (A) containing at least one polyisocyanate (B) of formula (I) and at least one OH group and solid at room temperature.

Polyisocyanates (B) of formula (I) are also referred to as tris (p-isocyanatophenyl) thiophosphates. As a solution to solvents, especially esters. A particularly preferred form is that which is commercially available as Bayer's Desmodur ^® RFE. According to Bayer's explanation, Desmodur ^® RFE is a 27% solution of Tristris (p-isocyanatophenyl) thiophosphate in ethyl acetate.

The ratio of the solid polyester resin (A) and the polyisocyanate (B) is, in the present invention, the stoichiometric ratio of the NCO group to the OH group ranges from 50: 1 to 100: 1, and / or to the polyisocyanate (B) It is used such that the weight ratio of the polyester resin (A) is in the range between 1.6 and 0.75, in particular between 1.2 and 0.8. In particular, the stoichiometric ratio of NCO groups to OH groups is between 50: 1 and 100: 1, and the weight ratio of polyester resin (A) to polyisocyanate (B) is between 1.6 and 0.75, and between 1.2 and 0.8. desirable.

In particular, the weight ratio of the polyester resin (A) to the polyisocyanate (B) is preferably 1: 1.

The polyester resin (A) contains at least one, preferably two OH groups, and is solid at room temperature as amorphous. The polyester also has a melting point of at least 140 ° C., in particular 150-160 ° C. as measured by the ring and ball method. On the other hand, the polyester resin (A) has a hardness of 70-85, in particular 75-85, most preferably 77-82 Shore D at 25 ° C.

Suitable polyester resins (A) are made from at least one dicarboxylic acid and at least one glycol. The polyester resin (A) preferably has a molecular weight of 12,000 g / mol, in particular 15,000-40,000 g / mol. The polyester resin (A) also has an OH number between 2-9, in particular between 3-6 mg KOH / g. In addition, polyester resin (A) is aromatic polyester resin.

The polyester resin (A) typically has the structure of formula (II) below.

In the above formula, the radicals R1 and R2 are independent of each other, divalent organic radicals, and n represents the number of repeating units.

Particularly preferred polyester resins (A) are sold in the 2000 series of Bostik's Vitel ^® product series. These products are specifically Vitel ^® 2100, Vitel ^® 2180, Vitel ^® 2190, Vitel ^® 2000, Vitel ^® 2200, Vitel ^® 2300, and Vitel ^® 2700. Especially preferred are the Vitel ^® 2200 and Vitel ^® 2200B.

A binder containing an isocyanate group is prepared by mixing a polyisocyanate (B) of formula (I) with a polyester resin (A) FMF containing at least one OH group. Such mixing allows the stoichiometric ratio of NCO groups to OH groups to be in the range of 50: 1 to 100: 1 or the weight ratio of polyester resin (A) to polyisocyanate (B) to a value between 1.2 and 0.8.

Prepared is an adduct of two molecules of polyisocyanate (B) and one molecule of polyester FM resin (A), which is an adduct of formula (III) having four free isocyanate groups.

In the preparation, at least one polyisocyanate (B) is first introduced into an organic solvent, followed by addition of at least one polyester resin, followed by stirring in an inert gas atmosphere. Suitable organic solvents for use to dissolve the polyester resin (A) are especially ketones or esters and the like. Preferably methyl ethyl ketone (MEK) or ethyl acetate.

In one embodiment, the primer composition comprises at least one organic solvent. Preferred solvents are ketones or esters, especially esters, preferably ethyl acetate.

In another embodiment, the primer composition comprises at least two organic solvents. An ester is included as a 1st solvent, and a ketone is included as a 2nd solvent. The solvents are ethyl acetate in the case of P 1 solvent and methyl ethyl ketone is preferred in the case of the second solvent.

The percentage of binder made from the polyester resin (A) mixture and at least one polyisocyanate (B) is 10-50% by weight, preferably 15-30% by weight, based on the weight of the primer composition.

In one preferred embodiment, the percentage of polyisocyanate (B) is by at least one polyisocyanate (B ') and / or by at least one polyisocyanate (B "), and / or at least one poly It can be replaced stoichiometrically by isocyanate (B '"). What is important here is that only a part of the polyisocyanate (B) is to be replaced and not a complete replacement of the polyisocyanate (B). Polyisocyanate (B ') is isocyanurate of hexamethylene diisocyanate (HDI), polyisocyanate (B ") is aromatic polyisocyanate based on tolylene diisocyanate (TDI), polyisocyanate (B'") Is a polymethylene polyphenyl called a raw material of hexamethylene 1,6-diisocyanate (HDI), diphenylmethane diisocyanate (MDI), isophorone diisocyanate (IPDI) and / or tolylene diisocyanate (TDI) or so-called MDI Oligomeric polyisocyanates of isocyanates. Such polyisocyanates are preferably polyisocyanates (B ') and (B ") of the kind sold by Bayer as Desmodur ^® L75 and Desmodur ^® N3300. The polyisocyanates (B'") are commercially available from Vestanat ^® by Degussa. that the T1890 or Vorante ^® kind of oligomer, sold as M580 rigs polyisocyanate sold by Dow are preferred.

Polyisocyanate (B) when the polyisocyanate (B ') and / or (B ") and / or (B'") added to the polyisocyanate (B) is used as a polyisocyanate to make a binder containing an isocyanate group The weight ratio of the polyester resin (A) to the sum of (B ') (B ") and (B'") preferably has a value between 1.6 and 0.75, in particular between 1.2 and 0.8.

In one embodiment, the primer composition comprises at least carbon black as filler. The carbon black present in the primer composition is preferably 1-20% by weight, especially 2-15% by weight, based on the weight of the primer composition.

It is advantageous to further provide the following polyisocyanates in the primer composition. Such polyisocyanates are for example hexamethylene 1,6-diisocyanate (HDI), 2-methylpentamethylene 1,5-diisocyanate, 2,2,4- and 2,4,4-trimethylhexamethylene 1 , 6-diisocyanate (TMDI), dodecamethylene 1,12-diisocyanate, cyclohexane 1,3- and 1,4-diisocyanate and mixtures of these isomers, 1-isocyanato-3,3,5 -Trimethyl-5-isocyanatomethylcyclohexane (= isophorone diisocyanate or IPDI), ferridro-2,4'- and -4,4'-diphenylmethane diisocyanate (HMDI), 1,4-di Socyanato-2,2,6-triethylcyclohexane (TMCDI), m- and p-xylene diisocyanate (XDI), tetramethylxylene 1,3- and 1,4-diisocyanate (TMXDI), 1,3 And 1,4-bis (isocyanatomethyl) cyclohexane, toluene 2,4- and 2,6-diisocyanate (TDI), and mixtures of isomers thereof, diphenylmethane 4,4'-, 2 , 4'- and 2,2'-diisosia Yit (MDI) and mixtures of isomers thereof, phenylene 1,3- and 1,4-diisocyanate, 2,3,5,6-tetramethyl-1,4-diisocyanatebenzene, naphthalene 1,5- Diisocyanate (NDI), 3,3'-dimethyl-4,4'-diisocyanatobiphenyl (TODI), 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane ( Isophore diisocyanate or IPDI), perhydro-2,4'- and -4,4'-diphenylmethane diisocyanate (HMDI), 1,4-diisocyanato-2,2,6-trimethylcyclohexane (TMCDI), tetramethylene 1,4-diisocyanate, 2-methylpentamethylene 1,5-diisocyanate, 2,2,4- and 2,4,4-trimethylhexamethylene 1,6-diisocyanate (TMDI) , Dodecamethylene 1,12-diisocyanate, lysine diisocyanate and lysine ester diisocyanate, 1,3- and 1,4-bis (isocyanatomethyl) cyclohexane (BIC), m- and p-xylene diisocyanate (m- and pX DI), 1,3,5-tris (isocyanatomethyl) benzene or bis (1-isocyanato-1-methylethyl) -naphthalene.

The primer composition may further comprise components such as catalysts, thixotropic agents, dispersants, wetting agents, preservatives, adhesion promoters, in particular alkoxysilanes and titanates, ultraviolet stabilizers and heat stabilizers, dyes, colorants and ultraviolet indicators.

Examples of suitable catalysts are tin catalysts, mismus catalysts and amine catalysts.

Suitable tin catalysts are especially organic such as dibutyltin dilaurate, dibutyltin diacetylacetonate, dibutyltin diacetate, dioctyltin dicarboxylate, mono- or dibutyltin thioesters, and dibutyltin dichloride. Contains tin components.

Suitable bismuth catalysts include in particular bismuth tracarboxylates, bismuth catalyst systems obtainable from bismuth compounds and aromatic nitrogen compounds disclosed in WO-A-2004 / 033519. Aromatic nitrogen compounds suitable for this purpose include 8-hydroquinoline.

It is noted that the primer composition improves the adhesion of the adhesive or seal material to the plastic and the painted surface and can therefore be used as a primer.

In particular, acrylonitrile-butadiene-styrene copolymers (ABS), polymethyl methacrylate (PMMA) and polycarbonates showed effective adhesion to plastics.

Painted surfaces include paint coated substrates such as glass, wood, metal, alloys, plastics, and inorganic substrates such as concrete, rock, or brick.

Particularly important paints include vehicle paints, in particular automotive paints. The most important paints are new generation automotive paints, in particular baking paints, which are known to contain one-component moisture-curable polyurethane adhesives or sealants and can cause adhesive problems.

The present invention also provides an adhesive bonding or sealing method. There are three ways to do this.

First way,

(a) applying a primer composition to the first substrate S1 to be bonded or sealed,

(b) applying an adhesive or sealing material to the primer composition applied to the substrate S1 and exposed to the flash;

(c) contacting the second substrate S2 with an adhesive or sealing material.

The second way is

(a ') applying the primer composition to the first substrate S1 to be bonded or sealed,

(b ') applying an adhesive or sealing material to the surface of the second substrate S2 of the same or different material as the first substrate S1,

(c ') contacting the primer composition exposed to the flash and applied to the first substrate S1 with the adhesive or the sealing material.

Third way,

(a ") applying the primer composition to the first substrate S1 to be bonded or sealed,

(b ") exposing the primer composition to flashes,

(c ') applying an adhesive or sealing material to the primer composition applied between the surfaces of the substrate S1 and the substrate S2.

All of the above methods may be used when the second substrate S2 is made of the same or different material as the first substrate S1.

The first substrate S1 is in particular a painted metal. Painted surfaces include, in particular, substrate surfaces of glass, wood, alloys, plastics or inorganic materials such as concrete, stone or bricks.

Particularly important paints include vehicle paints, in particular automotive paints. The most important paints are new generation automotive paints, in particular baking paints, which are known to contain one-component moisture-curable polyurethane adhesives or sealants and can cause adhesion problems.

When the second substrate S2 is different from the first substrate S1, the substrate S2 is particularly glass or ceramic.

In another example of the method of the present invention, in the case of the three methods described above, step (c) or (c '), or (c ") is followed by a step (d) of curing the adhesive or sealing material.

Various other adhesives or sealants may be used. Depending on the use and location of the structure to be bonded or sealed, the adhesive and seal material may be epoxy resin-based, isocyanate-based, (meth) acrylate based, or silane-terminated polymers ("STP" s) or silicone based. have. Examples of adhesives or sealants are room temperature cured adhesives or sealants, hot melt adhesives (known as "hotmelt"), dispersion based adhesives or sealants, pressure sensitive adhesives and the like.

The adhesive or sealing material may be a one component system or a multi component system.

However, in particular, one-component polyurethane adhesives or sealing materials are preferable. In this specification, the polyurethane adhesive and the polyurethane sealant include urethane and / or urea groups and prepolymers containing free isocyanate and / or alkoxy silane groups. The term "polyurethane" includes silane-terminated polyurethanes known in the art as conventional polyurethanes as well as "silane terminated polyurethanes (" SPUR ").

In addition to polyurethanes, it is also possible to use alkoxy silane-terminated polymers known in the adhesive or sealing material as the term "MS polymer".

The adhesive or sealing material is preferably a moisture-cured one-component polyurethane adhesive or sealing material. In particular, it is preferred to be a moisture-curing one-component polyurethane adhesive or a polyurethane sealing material, and in particular, a commercially available moisture-curing one-component polyurethane adhesive such as Sikaflex®rhk sold by Sika Schweiz AG can be used.

The present invention also provides a bonded or sealed product. These bonded or sealed products are obtained by the method as described above.

The bonded or sealed articles obtained according to the method of the invention are various. In particular in the various industrial sectors, in particular in vehicles, in particular automotive parts. The products may be surface mounted components. Surface-mounted parts of this kind are prefabricated modular parts used as modules in a manufacturing line, in particular, which are mounted or installed by adhesive bonding. These prefabricated surface mount parts are used as components of the vehicle.

Examples of surface mount components of this kind include trucks, locomotive caps for locomotives, and automotive sunroofs.

However, it can be used as a component of products such as furniture or building materials such as washers, walls or lifts.

Yes

primer  Preparation of the Composition

As shown in Table 1, the polyisocyanate is initially contained at least in part in a solvent, and then stirred, and the polyester resin is dissolved in the remainder of the solvent and slowly added dropwise while stirring with 1 at 30 ° C. in a nitrogen atmosphere. Stir for hours. The solution is then heated to 40 ° C. and stirred until the NCO content is constant. To this end, other solvents, a desiccant (p-toluenesulfonyl isocyanate "TI"), catalytic dibutyltin dilaurate "DBTL" and carbon black are placed in a fully sealed metal barrel and glass beads are added The metal canister is sealed and the contents are mixed for 1 hour by a Red Devil shaker device.

After the mixing process, the glass beads are removed and placed in an aluminum flask that tightly seals the primer composition.

Example REF-7 is a simple methyl ethyl ketone.

Table 1: Primer Composition

Test Methods

Application and curing

The primer composition is applied and coated on each of the various metal automotive paint panels using a brush. After exposure to flash for 30 minutes, use a high grade polyurethane adhesive Sikaflex®-250 DM-2, or a low grade polyurethane adhesive Sikaflex®-Ultrafast, available from Sika Schweiz AG. And apply as round beads.

The adhesive is then cured for 7 days at 23 ° C., 50% relative humidity (room temperature climate storage: “CS”) and the third bead is tested by the adhesion test described below. The samples are then submerged in water for another 7 days at 23 ° C. (underwater ““ WS ”) The adhesive is then bead tested against the other third beads. For another seven days, we tested at 40 ° C., 100% relative humidity wet climate for paint (“WCS”) or at 70 ° C., 100% relative humidity high temperature humidification climate (“HHS”) for plastic. .

Paint

 Metal panels with the following topcoat paint were used:

-HDG 4041 ("HDCT4041") from PPG

DuPont's RK 8046 ("RK8046")

DuPont's RK 4146 ("RK4146")

These paints showed inadequate adhesion properties for one-component polyurethane adhesives without primer pretreatment.

Adhesion Test (" Bead  exam")

The adhesion of the adhesive was tested by the "bead test". In this test, an incision is made at the end just above the adhesive surface, and the cut end of the bead is pulled from the substrate by the rounded end of the tongs. Carefully roll the beads onto the tip of the forceps and pull the cut vertically off the beads downward relative to the stripped substrate. The bead removal rate is selected by allowing the cut to take place for 3 seconds each time. The test length shall be at least 8 cm. The beads are evaluated by the adhesive remaining on the substrate after the tacky portion is pulled out. Adhesive properties are evaluated as follows by evaluating the sticky portion of the adhesive side:

1 ≥ 95% tacky part

2 ≥75-95% sticky part

3 ≥25-75% sticky part

4 ≤25% sticky part

5 = 0% sticky part (all sticky parts)

"P" in the evaluation indicates the separation of the primer from the substrate.

Test results with a tacky partial value of less than 75% are considered inadequate.

result

Adhesive test results are listed in Tables 2 and 3. These test results show that the adhesion to the paint for the primer composition of the present invention is greatly improved. Also, for example, B2-1, B2-2 and B2-3 are compared with B3-1, B3-2 and B3-3 to show that carbon black as an additive component in the primer composition in the adhesive exhibits the desired effect.

Comparative Examples REF-1 to REF-6 show the importance of the stoichiometric ratio of NCO groups to OH groups and the weight ratio of polyester resin A to polyisocyanate B for attachment to paint coated substrates.

Table 2: Bonding results of Sikaflex®-250 DM-2 for different paints after different types of storage. * n.m. indicates not measured.

Table 3: Adhesion results of SikaTack®-Ultrafast for different paints after different types of storage. * n.m. indicates not measured.

The primer composition of the present invention has the advantage of greatly enhancing the adhesion of the polyurethane adhesive and the sealing material to the paint and the plastic, in particular to the paint.

Claims (18)

It is made from a mixture of at least one polyisocyanate (B) of formula (I) below and an amorphous polyester resin (A) comprising at least one OH group and solid at room temperature and comprising at least one binder comprising an isocyanate group ,

The solid polyester resin (A) and polyisocyanate (B) have a stoichiometric ratio of NCO groups to OH groups in the range of 50: 1 to 100: 1 and / or polyester resins to polyisocyanates (B) A primer composition in such a proportion that the weight ratio of (A) is in the range 1.6 to 0.75, in particular in the range 1.2 to 0.8. A primer composition according to claim 1, wherein the polyester resin (A) is made from at least one dicarboxylic acid and at least one glycol. Primer composition according to claim 1 or 2, characterized in that the polyester resin (A) has a Shore D hardness in the range of 70 to 85, in particular in the range from 77 to 82, at 25 ° C. The primer composition according to any one of the preceding claims, wherein the pollingster resin (A) has an OH number of 3-6 mg / KOH. Primer composition according to any one of the preceding claims, further comprising at least one organic solvent, in particular an ester, preferably ethyl acetate. 6. A primer composition according to claim 5, characterized in that it comprises at least two organic solvents, in particular ethyl acetate and at least one other organic solvent, in particular a ketone, preferably methyl ethyl ketone. The primer composition according to any one of the preceding claims, further comprising at least one carbon black. 8. A primer composition according to claim 7, wherein the amount of carbon black is 1-202% by weight, in particular 2-15% by weight, based on the weight of the primer composition. The method of claim 1, wherein some of the polyisocyanates (B) are at least one polyisocyanate (B ′), and / or at least one polyisocyanate (B ″), and / or at least one polyisocyanate. (B '"), polyisocyanate (B') is isocyanurate of hexamethylene diisocyanate, polyisocyanate (B") is aromatic polyisocyanate based on tolylene diisocyanate, polyisocyanate (B ' ") Is an omeric of hexamethylene 1,6-diisocyanate (HDI), diphenylmethane diisocyanate (MDI), isophorone diisocyanate (IPDI) and / or tolylene diisocyanate (TDI) or polymethylene polyphenyl isocyanate Primer composition, characterized in that the polyisocyanate. The method of any one of the preceding claims, wherein part of the binder is made from a mixture of polyester resin (A) and at least one polyisocyanate (B) and is 15-30% by weight relative to the weight of the primer composition. Primer composition. Use as a primer composition according to any one of claims 1 to 10 as a primer for improving the adhesion of an adhesive or a sealing material to a painted surface. As a primer composition according to any one of claims 1 to 10 for improving the adhesion of adhesives or sealants to plastics, especially acrylonitrile-butadiene-styrene copolymers (ABS) or polymethyl methacrylate (PMMA). Usage. (a) applying a primer composition to the first substrate S1 to be bonded or sealed, (b) applying an adhesive or sealing material to the primer composition applied to the substrate S1 and exposed to the flash; (c) contacting the second substrate S2 with an adhesive or sealing material; or, (a ') applying the primer composition to the first substrate S1 to be bonded or sealed, (b ') applying an adhesive or sealing material to the surface of the second substrate S2 of the same or different material as the first substrate S1, (c ′) contacting the primer composition exposed to the flash and applied to the first substrate S1 with an adhesive or a sealing material; or (a ") applying the primer composition to the first substrate S1 to be bonded or sealed, (b ") exposing the primer composition to flashes, (c ") applying an adhesive or a sealing material to the primer composition applied between the surfaces of the substrate S1 and the substrate S2, wherein the second substrate S2 is connected to the first substrate S1; A method of making an adhesive binder or sealing agent made of the same or different material. 14. A method according to claim 13, wherein step (c) or (c ') or (c ") is followed by step (d) of curing the adhesive or sealing material. 15. The method of claim 13 or 14, wherein the adhesive or seal material is a moisture-curing one-component polyurethane adhesive or seal material. Method according to one of the claims 13 to 15, characterized in that the substrate (S1) is a paint, in particular a painted metal. A combined or sealed product by the method of any one of claims 13-16. 18. A combined or sealed product according to claim 17, wherein the product is a vehicle, in particular a part of a motor vehicle, or a part mounted on a vehicle or exterior of a motor vehicle.