JP3417561B2 - Topographic method - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to topographical support.
l) relates to a method of providing features.

TECHNICAL BACKGROUND US Pat. No. 5,086,088 discloses a latent thermosetting pressure sensitive adhesive composition comprising an acrylate pressure sensitive adhesive and an epoxy resin component which provides heat curing. The adhesive composition is disclosed to be useful in securing roof moldings to the body of an automobile.

BRIEF SUMMARY OF THE INVENTION The present invention relates to a novel method for imparting topographical or protective features to a permanent support comprising the steps of: a) first and second A carved curable sheet material having two major surfaces, comprising a latent thermosetting pressure sensitive adhesive throughout the major portion of its thickness and exhibiting pressure sensitive adhesive properties on its first major surface. B) contacting and adhering the first major surface of the sheet material to the permanent or temporary support, leaving the second major surface of the sheet material exposed. C) substantially thermosetting and substantially curing the sheet material in such a manner as to substantially allow an initial controlled mass flow of the sheet material in its thickness direction; Providing a substantially smooth transition between the second surface of the and the permanent or temporary support to which it is adhered; and d) adhering the cured sheet material to the temporary support. In some cases, the cured sheet material is peeled from the temporary support and then the first major surface of the sheet material is fixed (eg, adhered) to the permanent support.

In a preferred method, the sheet material is adhered to the permanent support in the first case.

The method of the present invention applies a sheet material to an automobile part or body of primed or unprimed metal to seal the metal part or emblem or insignia.
Or, it finds particular use in providing design elements, such as trim. The resulting laminate is aesthetic. Because the cured sheet material exhibits a smooth, rounded edge to the support and can be painted or otherwise decorated as needed to fit or otherwise accent other parts of the vehicle. Because it is.

Another application of the method of the present invention is in the manufacture of signs and the like which are subsequently adhered to a permanent surface by an adhesive separate from the sheet material used in the manufacture of signs or other articles.

DETAILED DESCRIPTION OF THE INVENTION The sheet material used in the method of the present invention comprises a latent thermosetting pressure sensitive adhesive. By "pressure sensitive adhesive" is meant an adhesive which exhibits pressure sensitive adhesive properties at the temperature at which it contacts the permanent or temporary support in step b) of the method. Generally, the temperature required for that step will be between ambient temperature and about 400 ° F (205 ° C). It is presently preferred that the adhesive exhibits pressure sensitive adhesive properties at ambient temperature, eg 22 ° C.

The composition of the thermosetting pressure sensitive adhesive contained within the sheet material, when used in the method of the present invention, has a modulus of elasticity that provides a smooth transition between the exposed surface of the sheet material and the adhered substrate. It is lowered to allow a controlled flow of sheet material at its edges that results in a section. By "controlled flow" is meant that there is no substantial change in the dimensions of the sheet material in its x- and y-planes defining the first major surface. Typically, the sheet material will be cut or shaped into the desired shape or size by methods such as die-cutting or knives or laser slitting that result in sharp transition lines. After the controlled flow described above occurs, the latent cure or crosslinking chemistry is activated to cure the sheet material and the pressure sensitive adhesive therein. With such curing, there can be a loss of substantially all pressure sensitive adhesive properties of the sheet material. In a preferred method of the invention, the controlled mass flow and subsequent thermosetting reaction results from heating the sheet material.

The sheet material used in the method of the present invention comprises a latent thermosetting pressure sensitive adhesive over most of its thickness. Preferably, the sheet material comprises an adhesive throughout its entire thickness.

The thermosetting pressure sensitive adhesive preferably comprises i) a prepolymer (ie, typically partially polymerized in a viscous syrup between about 100 and 10,000 centipoise) comprising acrylic acid or methacrylic acid ester. Or syrup of monomer; ii) epoxy resin; iii) photoinitiator; and iv)
It comprises a photochemical reaction product of the starting material, which comprises a heat-activatable curing agent for the epoxy resin. Such compositions can be conveniently coated and polymerized in various thicknesses, including relatively thick sections.

The photopolymerizable prepolymer or monomer syrup comprises an acrylic acid or methacrylic acid ester, and optionally a copolymerizable reinforcing comonomer. Acrylic acid or methacrylic acid ester has about 4 in its alcohol portion.
Are monofunctional acrylic or methacrylic acid esters of non-tertiary alcohols having from 1 to about 12 carbon atoms. This type of ester includes n-butyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate,
Includes octyl acrylate, isooctyl acrylate, decyl acrylate and dodecyl acrylate. Mixtures of esters can be used.

Copolymerization-enhancing monomers, when used, are preferably monomers such as acrylic acid, isobornyl acrylate, N-vinylpyrrolidone, N-vinylcarolactam, N-vinylbiperidine, N, N-dimethyl. It is selected from the group consisting of acrylamide and acrylonitrile. Preferred reinforcing monomers contain nitrogen, such as the nitrogen-containing monomers listed above. The toughening monomer will generally be chosen such that the homopolymer prepared therefrom has a higher glass transition temperature than the homopolymer prepared from the acrylic or methacrylic acid ester used.

In the case where the prepolymer or monomer syrup comprises both acrylic acid or methacrylic acid ester and reinforcing monomer, the acrylic acid or methacrylic acid ester will generally be present in an amount of about 50 to 95 parts by weight. And the reinforcing comonomers will be present in corresponding amounts of about 50 to 5 parts by weight. One of ordinary skill in the art will be able to vary the nature and amount of the reinforcing monomer to obtain the desired pressure sensitive adhesive properties.

Glycidyl methacrylate as a starting material with acrylic or methacrylic acid ester and a strengthening monomer,
It is also desirable to use glycidyl acrylate or other epoxy-functional monomers. Such an epoxy-
The functional monomer, if used, is preferably
It will be present in an amount of about 0.1 to 10 parts by weight per 100 parts by weight of all monomers used.

Acrylic copolymers useful in pressure sensitive adhesives are very stable compositions. Due to their stability, the sheet materials used in the method of the present invention can be subjected to the heating conditions necessary to cure the epoxy resin without decomposition of the pressure sensitive adhesive portion of the composition. . Other types of pressure sensitive adhesives may partially or completely lose their adhesiveness, allowing them to adhere prior to being subjected to the conditions (ie, time and elevated temperature conditions) required for thermosetting the epoxy resin. Cause detachment of the sheet material from the support, such as a structural portion that has been made.

Moreover, both the photopolymerizable acrylic or methacrylic prepolymer or monomer syrup and the photopolymerized polymer form a stable mixture with the epoxy resin.

Useful epoxy resins have an average of 1 or more per molecule,
And preferably it can be selected from the group of compounds containing at least two epoxy groups. Epoxy resin is
It is preferably either liquid or semi-liquid at room temperature for handling purposes. Most preferred is a mixture of liquid and solid resin. Representative examples include phenolic epoxy resins, bisphenol epoxy resins, hydrogenated epoxy resins, aliphatic epoxy resins, and halogenated bisphenol epoxy resins. Mixtures of epoxy resins can be used.

The preferred epoxy resin includes bisphenol epoxy, and the most preferred epoxy resin is
It is a diglycidyl ether of bisphenol-A formed by the reaction of bisphenol-A with epichlorohydrin.

The epoxy resin will generally be present in an amount of about 25 to 120 parts by weight based on 100 parts by weight of prepolymer or monomer syrup.

The photoinitiator used to polymerize the prepolymer or monomer syrup can be, for example, any conventional free radical photoinitiator that can be activated by ultraviolet light. Examples of suitable photoinitiators are 2,2-
Dimethoxy-1,2-diphenylethan-1-one (Ciba
-Irgacure ^TM 651 available from Geigy Corporation)
Is. The photoinitiator is typically used in an amount of about 0.01 to 5 parts by weight per 100 parts by weight of prepolymer or monomer syrup.

A heat-activatable curing agent is added to effect curing of the epoxy resin under heating. The hardener may be of any type, but is preferably an amine type hardener selected from the group consisting of dicyandiamide or polyamine salts. These are available from a variety of sources, for example Omicure ^™ is Omicron C
available from hemical, and Ajicure ^TM is Ajin
Available from omoto Chemical. The heat activatable curing agent will typically be used in an amount of about 0.1 to 20 parts by weight, and preferably 0.5 to 10 parts by weight, per 100 parts by weight of the prepolymer or monomer syrup. . Sufficient hardener must be used to achieve cure of the epoxy resin.

The heat to which the sheet material is exposed may be insufficient to fully cure the epoxy resin, for example, due to the many locations in which the sheet material can be used in an automotive painting cycle. In these cases, it may be advantageous to add an accelerator to the prepolymer blend,
This allows the resin to fully cure at lower temperatures or even when exposed to heat for a short period of time. Imidazole and urea derivatives are used as accelerators because of their ability to extend the shelf life of acrylic-based materials containing uncured epoxy resins, as demonstrated by the examples herein. On the other hand, it is particularly preferable in the practice of the present invention. The currently most preferred imidazoyl for use in the present invention is 2,4-
Diamino-6- (2'-methyl-imidazoyl) -ethyl-s-triazine isocyanurate, 2-phenyl-4
-Benzyl-5-hydroxymethylimidazole, hexakis (imidazole) nickel phthalate and toluene bisdimethylurea. Such accelerators can typically be used in amounts up to about 20 parts by weight per 100 parts by weight of prepolymer or monomer syrup.

It may be desirable to include a chain transfer agent in the starting material used to make the thermosetting pressure sensitive adhesive to provide a sheet material that exhibits the desired flow characteristics upon heating. By including a chain transfer agent in such a starting material, it becomes easy to obtain a low molecular weight acrylic polymer having a broader molecular weight distribution.

Other useful materials that can be blended into the thermosetting pressure sensitive adhesive include, but are not limited to, extenders, pigments,
Fiber, woven and non-woven, foaming agent, antioxidant,
There are stabilizers, flame retardants, and viscosity modifiers.

The sheet material used in the method of the present invention is preferably produced by premixing a photopolymerizable monomer and a photoinitiator. This premix is then partially polymerized to a viscosity in the range of about 500 cps to about 5,000 cps to give a coatable syrup. Alternatively, the monomer can be mixed with a thixotropic agent, such as fumed hydrophilic silica, to a coatable thickness. Other ingredients, such as epoxy resin and heat-activatable hardener, are then added to the syrup prior to photopolymerization.

The composition is a flexible carrier web, preferably transparent to UV radiation and an inert atmosphere, i.e.
Coated on a silicone release liner that is polymerized in a substantially oxygen free atmosphere, such as a nitrogen atmosphere. By coating the layer of photoactive coating with a plastic film that is substantially transparent to UV light and irradiating through the film in air as described in US Pat. No. 4,181,752 (Martens et al). , A sufficiently inert atmosphere can be achieved. The liner can be removed when it is desired to use the sheet material obtained in the method of the present invention.

The method of the present invention has numerous applications in industry. One application of the method is in the automotive industry as it can be used in the process for sealing metal joints in motor vehicles. According to the above method, the sheet material is first produced, for example, by the method described above. The sheet material will then be applied over the joint to be sealed. Complete sealing and bonding will be obtained due to the flow of the sheet material prior to curing. An aesthetic surface appearance is achieved as a result of the controlled flow of edges of the sheet material. The exposed surface of the cured sheet material can then be painted or otherwise decorated to conform to the vehicle body.

Another application of the method of the invention is in the application of emblems or insignia or design elements to surfaces, such as the body of an automobile. An example of an emblem or insignia is a car manufacturer's logo. An example of a design element is a trim to strengthen and accentuate the curve of an automobile body and to protect primed metal substructures without the need for complex metal stamping to obtain its shape. . In such a method, the sheet material is, for example,
It is first shaped by die-cutting into the shape of the desired emblem or insignia or design element. Therefore, the practice of the method of the present invention provides an aesthetically pleasing emblem or insignia with smooth lines compared to the adhered surface.

In yet another application of the method of the present invention, the support to which the sheet material is first adhered is a temporary support, such as a disposable liner. After curing of the sheet material in such a manner as to provide controlled flow of its edges, the cured sheet material is secured to a permanent support (eg, through the use of an adhesive system that is different from the sheet material itself (eg, Can be adhered). This is because the cured sheet material may substantially lose pressure sensitive adhesive properties. In this way, the method of the invention can be used to provide a surface, eg a wooden door, with a shaped, cured sheet material, eg a sign.

The invention will be further described by the following non-limiting examples.
Here, all parts are expressed as parts by weight unless otherwise specified.

Test Method 250 ° F (121 ° C) Shear Creep Flow Test: 3/4 inch
^Two pieces of tape are placed on a 2 "x 6" anodized aluminum panel. 2 inches × weighing about 5.5g
Place 1 inch piece of anodized aluminum on top of the tape, parallel to the base panel; contact 15 l
This is done by rolling twice with the wheel of b. Draw a line to mark the initial position of a small piece of aluminum. The panel is then hung vertically in a rack and placed in a 250 ° F oven for 30 minutes. After this time, the rack was removed and cooled. Upon cooling, remove the panel from the rack and mark the location of the small piece of aluminum by drawing. The difference between the first position and the position after heating is measured in centimeters. If the tape melts very easily and a small piece of aluminum falls off, record a> 15 cm reading.

Melt Flow Visual Observation: Apply 1 inch ² strips of tape to a paint primer, eg (Advanced Coating Technology,
PPG ED-3150 (from Inc., Michigan) on a steel panel electro-coated. The panel with the tape is placed horizontally in a 250 ° F oven for 30 minutes, then removed and allowed to cool to room temperature. A visual inspection of the tape is made based on the following criteria: 1 = no flow, tape has right end.

  2 = Some flow, tape with slightly rounded edges.

  3 = more flowable, tape has very rounded edges.

  4 = Better flow, tape begins to become liquid.

  5 = most fluid, tape became liquid.

Example 1 n-Butyl acrylate / with a monomer ratio of 80/20
100 parts of a mixture of N-vinylcaprolactam, 0.04 parts of Ir
Blended with gacure ^TM 651 and under constant nitrogen purge to a viscosity of about 3000 cps ultraviolet (UV) light source (Sylvania F20T 12
It was photopolymerized by BL). In addition, 0.1 part (Ciba-Gei
(available from gy Corporation) Irgacure ^™ 651, 50 parts Epon ^™ 1001 (diglycidyl ether of bisphenol A available from Shell Chemical Co.), 30 parts Epon ^™
828 (diglycidyl ether of bisphenol A available from Shell Chemical Co.), 5.94 parts micronized dicyandiamide curing agent, 5.04 parts toluene bisdimethylurea (Omicure available from Omicron Chemicals Inc.
^TM 24) and 0.05 part of 3-mercaptopropionic acid as a chain transfer agent was added. This mixture was thoroughly mixed with a laboratory mixer for about 15 minutes and slowly kneaded with a ball mill mixer for about 16 hours. The mixture was then knife coated at 40 mils (1.016 mm) thick onto a clear silicone coated polyester liner having a thickness of about 0.05 millimeters and coated with a second similar polyester liner. The coated mixture was EIT (Electronic Instrumentation
& Technology, Inc., Sterling, VA) as measured using a Uvirad radiometer (Model No. VR365CH3) from 1.82 mWatts / cm ² above the web and 1.73
Photopolymerized using UV light sources above and below the tape with lower intensity. The total UV energy was 450 millijoules / cm ² .

Removing the liner from the previously obtained adhesive sheet material,
The sheet material was then glued to the steel sheet. The resulting laminate was then placed in an oven maintained at 270 ° F (132.2 ° C) for 20 minutes. During this heating cycle, the edges of the sheet material flowed to provide a smooth transition line between the top of the sheet material and the steel sheet.

Example 2 A sheet material was prepared according to the procedure of Example 1, and
Converted to tape with a width of 1/2 inch (1.27 cm). The tape was placed in a recessed lap joint made by spot welding two pieces of steel. Base Goat (“NHU9039 available from PPG, Pittburg, PA
4R ") was applied directly onto the tape, and the lap joint / tape laminate was placed in an oven maintained at 270 ° F for 20 minutes. Then clearcoat (PPG, Pittburg, P
DCT 5000) available from A. was applied and the lap joint / tape laminate was subjected to a second baking cycle as before. The resulting seal wrap joint had an aesthetically pleasing paint appearance.

Example 3 An adhesive sheet material was prepared using the components (and their amounts) and procedure described in Example 1. However, no chain transfer agent was included, and the amounts of micronized dicyandiamide curing agent and toluenebisdimethylurea added to the coatable syrup were 10.8 parts and 9, respectively.
It was 02 copies. The sheet material was converted to tape, which was then glued to a recessed lap joint and all processed as described in Example 2. During this process, the edges of the tape flowed to a lesser extent than was obtained in Example 2 and provided a smooth transition line between the top of the tape and the recessed lap joint.

Examples 4-6 The ingredients listed in Table 1A were mixed to prepare three formulations differing only in the type of nitrogen-containing copolymerizable monomer used. The ratio of butyl acrylate to nitrogen-containing copolymerizable monomer in the syrup was varied to maintain the nitrogen-containing monomer on an equimolar basis. All quantities are represented by weight.

Syrup: The acrylate component was blended with a photoinitiator and photopolymerized with an ultraviolet (UV) light source under a constant nitrogen purge to create a partially polymerized "syrup". These syrups were then blended with epoxy and the epoxy cure and other ingredients were mixed until a solution was achieved.

Coatings: These resulting formulations were degassed in vacuo and fed into the nip of a knife coater between two clear biaxially oriented polyethylene terephthalate films whose opposite surfaces had a silicone release coating. The knife coater was adjusted to provide a coating thickness of about 40 mils. Coating exiting from the knife coater, 224Mj in the intensity of 1.29mW / cm ² / cm
^The pressure sensitive transfer tape was obtained by exposing each side of the coating to a total energy of ² and irradiating with a UV light source. The properties of these tapes are shown in Table 1B.

Example 7 As an additional feature of these systems, the cured transfer tapes of Examples 4-6 (140 ° C. for 30 minutes) were subjected to analysis by transmission electron microscopy, all samples showing epoxy domains in the continuous acrylate phase. However, the average size of the majority of those epoxy domains was larger (0.75) for the sample of Example 5 than the sample of Example 4 (0.18 micron) or the sample of Example 6 (0.25 micron). micron).

Examples 8-11 The ingredients listed in Table 2A were mixed together to prepare four formulations with different non-polar monomers (BA or IOA) used and nitrogen-containing monomers (NNDMA or NVC) used. This formulation was syruped and coated by the procedure described in Examples 4-6. The coated mixture was photopolymerized using a UV light source (located above and below the tape) with an intensity of 1.1 mW / cm ^{2 to} 2.5 mW / cm ² .
The total UV energy was 797 mJ / cm ² . The properties of these tapes are shown in Table 2B.

Examples 12-16 NVC in a syrup was prepared by mixing the ingredients listed in Table 3A.
Five formulations were prepared with increasing amounts of NNDMA in combination with. This formulation was syrupped and coated using the procedure described in Examples 4-6.
The coated mixture was photopolymerized using a UV light source (located above and below the tape) with an intensity of 1.1 mW / cm ^{2 to} 2.5 mW / cm ² . The total UV energy was 396 mJ / cm ² . The properties of these tapes are shown in Table 3B.

Example 17 A formulation was prepared generally according to the procedure of the previous example using the ingredients (and amounts) listed in Table 4 below.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kitano, Shuichi United States, Minnesota 55133-3427, Saint Paul, Post Office Box 33427 (No address) (72) Inventor Ito, Akira United States, Minnesota 55133-3427, Saint Paul , Post office box 33427 (No address) (56) Reference JP-A-63-83184 (JP, A) JP-A-60-173076 (JP, A) JP-A-2-4882 (JP, A) European patent application Publication 386909 (EP, A 1) (58) Fields investigated (Int.Cl. ⁷ , DB name) C09J 7/00 B05D 7/24 B29C 65/48 C09J 5/06

Claims (10)

(57) [Claims] 1. A method of imparting topographical or protective features to a permanent support comprising the steps of: a) a curable sheet material having first and second major surfaces, the thickness of which is: Providing a sheet material comprising a latent thermosetting pressure sensitive adhesive over a major portion of the ridge and exhibiting pressure sensitive adhesive properties on the first major surface; b) providing permanent support to the first major surface of the sheet material. Contacting and adhering to a body or temporary support, leaving the second major surface of the sheet material exposed; c) the sheet material in a manner that allows an initial controlled flow of the sheet material. Substantially heat-curing and substantially curing the second major surface of the sheet material and the permanent or temporary support to which the sheet material is adhered. Providing a substantially smooth transition between; and d) peeling the cured sheet material from the temporary support when adhering the cured sheet material to the temporary support, and Then securing the first major surface of the sheet material to the permanent support, wherein the exposed second major surface of the cured sheet material is topographically or protective to the permanent support. The method for providing an optional feature. 2. The method of claim 1, wherein step b) comprises contacting and adhering the first major surface of the sheet material to the permanent support. 3. The method of claim 1 wherein step b) comprises contacting and adhering the first major surface of the sheet material to the temporary support. 4. The method of claim 1, wherein step c) is performed by heating the sheet material. 5. The step c) heats the sheet material to a temperature sufficient to reduce its elastic modulus and thereby allows the controlled flow as described above, after which the sheet material is The method of claim 4, performed by heating the sheet material to a higher temperature that results in a substantial thermal cure and a substantial cure. 6. The method of claim 5, wherein step c) is performed by continuously increasing the temperature of the sheet material. 7. The method of claim 1, further comprising the step of painting a second major surface of the sheet material prior to step c). 8. The method of claim 1, further comprising painting the second major surface of the sheet material after step c). 9. The method of claim 1, wherein the thermosetting pressure sensitive adhesive exhibits pressure sensitive adhesive properties at ambient temperature. 10. The sheet material comprises the thermosetting pressure sensitive adhesive substantially throughout its thickness.
The method described in.