DE3225691A1 - Process for the production of improved safety glass laminates - Google Patents

Abstract

A novel and improved process for the production of impact-resistant laminates which are transparent to visible light is disclosed in which a photocurable composition is introduced between two layers of a sheet material which are transparent to visible light, and is exposed to actinic radiation. The photocurable composition is thereby cured and forms a structural and adherent intermediate layer for the laminate.

Description

Method of Making Improved Safety Glass Laminates Die Invention relates to a method for producing impact-resistant laminates and resulting improved laminates, particularly for use by Light-curable epoxy prepolymer compositions for the formation of an intermediate structural adhesive layer between at least two layers of sheet material permeable to visible light, thereby creating a safety glass laminate that has improved properties has over a wider temperature range.

The use of a laminate structure for a shatterproof glass for Automobile windshields and the like are known.

Generally there is an intermediate plastic layer between two Panes of glass. The plastic intermediate layer, which is used to prevent foreign objects that are on Hit the windshield, distract, and in the event of a break the outer Glass layer, fragments of glass stick to the intermediate layer, what the dangers that are associated with flying glass. Early conventional glass laminates had intermediate layers of a nitrocellulose material. The nitrocellulose interlayer does not adhere well to the glass. Such laminates are better than non-laminated ones Mirror glass, however, lacks sufficient impact resistance for most purposes.

These laminates also tend to discolor with age, making them unsatisfactory for use as windshields for automobiles power.

Developments in the field of vinyl resins have led to corresponding developments Advances in the field of glass laminates resulted.

In particular, the development of polyvinyl acetal resins, by Robertson in U.S. Patents 2,162,678, 2,162,679 and 2,162,680, and in particular the partial polyvinyl acetal resins described by Reid in US Pat. No. 2,120,628 made possible an improved safety glass laminate for windshields, the has served as a standard in the automotive industry for years. A partial polyvinyl acetal resin becomes incomplete by reacting polyvinyl alcohol with one to form one acetalized polyvinyl resin produced a sufficient amount of aldehyde. Ester plasticizers are mixed into the resin to provide a softened resin, which is then after any suitable method such as extrusion, calendering, or evaporation, etc. is formed into sheets or foils. Water is made by drying the plate, slide or orbit away at about 600C. The dried resin plate is then carefully leaning against a previously cleaned glass plate, being careful the inclusion of air bubbles between the plastic interlayer and the Prevent glass. A second sheet of glass is then put on the other side of the resin sheet brought and the resulting 1Sandwich "passed between a pair of rollers, squeeze out any remaining air. The glass plates are then through Heat and pressure bound to the resin interlayer.

Typically, the composite is placed in a steam-heated autoclave brought and completely covered by ethylene glycol. The temperature in the autoclave is increased to 90 to 1500C and the pressure by compressed air to 10.5 to 21 bar (150 up to 300 psi). These conditions are persisted long enough to allow binding, whereupon the glycol slowly circulates with cold Water is cooled using the pressure is kept constant to the Prevent the formation of air bubbles between the plastic and the glass. if the glycol has cooled to about 750C, the pressure is released, the bond removed and the laminate brought to room temperature. The laminate is then thorough washed to remove any adhering glycol. Those following this latter procedure safety glass laminates produced have good clarity, adhesiveness and Strength and are elastic and stretchable at the same time. There is a defect in these laminates in that the polyvinyl butyral resin intermediate layer tends to stiffen and with lower temperatures become brittle, which makes them more resistant to shocks reduces in winter driving conditions. In addition, the procedure requires to manufacture these conventional laminates a variety of stages, including a Amount of temperature control and dfe use of solvents belong to what the Increases production costs.

More recently there have been other advances in the polymer field, so that new liquid resources or masses are now available that are generated by heat or light can be hardened into solid materials. Examples of such means are described in U.S. Patents 4,173,551 and 4,026,705.

Of particular interest are U.S. Patents 4,058,401 and 4,090,936. The photocurable agents described therein include an epoxy-containing one organic material, a compatible polymer and an aromatic complex salt as Photo starter in the form of a Group VIa aromatic onium salt.

The photocuring of these agents occurs upon exposure to any one actinic radiation at a wavelength in the ultraviolet and visible spectral range emitting radiation source. The means can alternatixr by electron irradiation hardened. The agents are solvent-free liquid agents of 1GO% solids and are photocurable at room temperatures or below to tack-free state. The hardened material adheres well to metal and other surfaces and has good resistance to caustic and plating chemicals. Heretofore, these gowns have been used as photoresist films in the manufacture of printed matter Circuits, of printing plates and the like. Found.

It has now been found that those described in such patents Photohardenable agents are astonishingly suitable for the manufacture of shock-resistant materials Laminates according to the invention.

According to the invention, a new and improved method for production Created from visible light permeable laminates that are suitable for use suitable as automobile windshields. According to the invention, a liquid, photohardenable Means between at least two visible light permeable layers of disk or plate material is inserted to form an intermediate layer. The photohardenable Agent is then exposed to actinic radiation, which has a photohardening reaction initiates. The photocuring can continue until it is practically finished. One firm, structural and adhesive intermediate layer is formed that attaches to the two adjacent layers of sheet material are bonded, making a safety glass laminate product is available.

The photocurable agents for use in accordance with the invention include an epoxy prepolymer and an effective amount of an aromatic sulfonium complex salt as a photo starter.

In a preferred embodiment, the photohardenable agent comprises 3,4-epoxycyclohexamethyl-3,4-epoxycyclohexane carboxylate and triphenylsulfonium hexafluoroantimonate.

The sheet materials permeable to visible light can be glass or plastics, such as poly (bisphenol A-carDonate) or poly (methyl methacrylate) or any obviously equivalent material. Foil radiation source for triggering The photohardening reaction can be any actinic oil, such as silver -, Xenon, sole arc and tungsten wire lamps, sunlight, etc., be.

The method according to the invention greatly simplifies production of security laminates compared to conventional methods.

Further objects, advantages and features of the invention result from the following detailed description.

In the method according to the invention for producing a visible one Light-transmitting, impact-resistant laminate becomes a liquid, photo-curable agent between at least two layers of visible light transmitting plate material then the actinic radiation interlayer photocurable agent exposed and the subsequent photocuring reaction practically complete expired. The liquid photocurable agent is produced by this procedure Hardened to a solid intermediate structure that adheres to each layer of the adjacent Plate material is adhesively bound and thereby forms a shock-resistant laminate.

The photocurable agents for use according to the invention generally comprise an epoxy prepolymer and an effective amount of an aromatic complex salt as a photoinitiator selected from an onium salt of a Group Va element and an onium salt of a Group VIa element and an aromatic halonium salt. In detail, the epoxy prepolymers for use according to the invention comprise a mixture with an epoxy-containing organic material and optionally, but preferably, a second organic polymer. The epoxy-containing materials useful in the photocurable agents of the present invention include organic compounds having an oxirane ring which are polymerizable by opening the ring. Such materials, commonly referred to as epoxies, include monomeric epoxy compounds and polymer-type epoxides and can be aliphatic, cycloaliphatic, aromatic, or heterocyclic. The materials useful in the present invention generally have an average of 1 to about 5 polymerizable epoxy groups per molecule. The polymeric epoxides include linear polymers with terminal epoxy groups - (e.g. a diglycidyl ether of a polyoxyalkylene glycol), polymers with skeletal oxirane units (e.g. polybutadiene polyepoxide) and polymers with poxy groups attached (e.g. a glycidyl methacrylate polymer or copolymer). The epoxides can be pure compounds, but are generally mixtures with one, two or more epoxide groups per molecule. Thus, epoxies used can be mixtures of different types of materials so long as the "average" epoxy functionality of the mixture is in the range of about 1 to 5. The "average" number of epoxy groups per molecule is determined by dividing the total number of epoxy groups in the epoxy-containing material by the total number of epoxy molecules present.

It was found that the average functionality of the epoxy in the agent must be in the range of about 1 to 5 in order to achieve the appropriate hardening of the Means to be achieved after irradiation, but the photocured agent in its firm or hardened form still elastic and stretchable.

These useful epoxi.dhaltigen materials can be of low molecular weight from monomeric materials to polymers, and can vary widely in nature Skeleton and the substituent groups vary. For example, the skeleton be of any kind and the substituent groups on it any group free of active hydrogen atom reactive with an oxirane ring at room temperature.

Examples of possible substituent groups include halogens, ester groups, Ethers, sulfonate groups, siloxane groups, nitro groups, phosphate groups, etc. The molecular weight the epoxy-containing materials can vary from 58 to about 100,000 or more.

Preferred epoxy-containing materials include those containing the cyclohexene oxide group contain en, such as the epoxycyclohexanecarboxylates, for example 3,4-epoxycyclohexylmethyl-3,4-epoxy-cyclohexanecarboxylate, 3,4-epoxy-2-methyl-cyclohexylmethyl-3,4-epoxy-2-methylcyclohexane carboxylate and bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate. For a more detailed list of useful epoxies of this type, see US Pat 3 117 099 referenced. Many other suitable epoxy-containing materials that can be used in accordance with the invention Can find application are suitably described in the above-mentioned patents.

The organic polymer, dals optionally in the photo-curable Means for the inventive use is included, is with the epoxy Compatible material. The amount of polymer present can be from about 5 to about 90 @, based on the weight of the epoxy-containing material, vary, with the preferred amount range about 40 to 60 wt.%, Based on the weight of the epoxy-containing Materials, is to make the liquid photocurable agent having a useful viscosity to deliver.

The optionally present polymer can be of acrylate, methacrylate or adipate monomers (i.e. the polymer can be a homopolymer or a copolymer be), although copolymers of styrene and allyl alcohol were found to be useful hubs, as well as polyvinyl butyral polymers. It was found that the organic polymer a glass transition temperature in the range of about -400C to 105 ° C (preferably 50 up to 600C).

The term "polymer" as used herein also means oligomers (e.g. B. Materials with a number average molecular weight down to about 1000) as well as high polymers (which have a number average molecular weight in the range of about 1,000,000} comprehensive. Preferably the number average molecular weight is of the organic polymer in the range of about 15,000 to 60,000.

Although the organic polymer has been found to be one or more Hydroxyl groups or other groups, e.g. B.

Mercapto groups, can carry, is the optionally present polymer otherwise free of "active hydrogen". The term "active hydrogen" remainder is well known and is commonly used in the art and as used herein means he active hydrogen, determined according to that of Zerewitinoff in J. Am. Chem. Soc., 49, 3181 (1927) described method, which is incorporated by this reference in the present Registration is recorded. Of course, the organic polymer comes in handy too free from groups that may be thermally or photolytically unstable, d. h., that Material does not decompose and does not release volatile components at temperatures below about 1000C or in the presence of actinic light or electron irradiation, under conditions during the desired curing for the photohardenable agent may occur.

Thus, the organic polymer can be hydroxy-functional or mercapto-functional or it can be essentially non-functional (i.e. practically none with the Containing epoxy reactive groups) or a mixture of such types. If that organic polymer having hydroxyl or mercapto functionality, the group can (or groups) be terminal or depend on a polymer or copolymer. That Equivalent weight (i.e., number average equivalent weight) of useful hydroxy functional and mercapto-functional organic polymer is at least about 200 and preferably in the full range about 600 to 1500.

Preferred organic polymers which may be present can be derived from different monomers originate. Such monomers include acrylates, methacrylates or dicarboxylic acids, e.g. B.

Adipic acid and the like. The resulting polymer preferably has a Glass transition temperature in the range from -400C to t050C. For example, are representative the following acrylate and methacrylate monomers can be used: methyl methacrylate n-butyl acrylate Hydroxäthylacrylat Hydroxyäthylmethacrylat n-Butylmethacrylat Hydroxypropylacryic ', Hydroxypropyl methacrylate ethyl acrylate Preferably the acrylate, methacrylate and adipate monomer esters of acrylic, methacrylic or adipic acid with an aliphatic Alcohol with 1 to 4 carbon atoms or an aliphatic diol with 2 to 4 Carbon atoms.

Useful condensation polymers are derived from dicarboxylic acids such as Adipic acid and terephthalic acid, and diols such as butanediol, neopentyl glycol and like., from. A preferred member of this family is poly (1,6-hexylene-o-phthalate).

Other suitable polymers that may be present include polyvinyl butyral polymers, z. Of the type available from Monsanto in the "FlButvar" series. For example "3u.var B-76" is a polyvinyl butyral polymer having a hydroxyl content (expressed as% polyvinyl alcohol) from 9 to 13 8, an acetate content (expressed as * polyvinyl acetate) from 0 to 2.5 8 and a butyral content (expressed as polyvinyl butyral) of 88 %. The glass transition temperature of such a polymer is in the range from 48 to 550C.

The photocurable agents for use in the present invention include also an aromatic complex salt as a photo starter.

Albeit the aromatic sulfonium complex salts as photo starters s.nd preferred, there are many aromatic complex salt photo-starters available on the Area known. are and can be used according to the invention. In general the photoinitiators are onium salts of an element of group Va, onium salts a Group VIa element and aromatic halonium salts. These After UV or electron irradiation, complex salts are able to form units which Start epoxy reactions.

Specifically, preferred photosensitive aromatic onium salts of Group VIa elements can be represented by the formula illustrated can be a source of a protic acid such as eortrifluoride, phosphorus pentafluoride, arsenic pentafluoride, etc. when exposed to radiant energy. A variety of radiation polymerizable agents can be created by incorporating the photosensitive aromatic onium salt into a variety of cationically polymerizable organic materials as defined above Formula are defined: [(R) a (R1) b (R2) cX] a + [MQe] - (ef) where R is a monovalent a: aromatic organic radical, R1 is a monovalent organic aliphatic radical selected from alkyl, cycloalkyl and substituted Alkyl, R2 is a multivalent organic] radical which forms a heterocyclic or condensed ring structure, selected from aliphatic radicals and aromatic radicals, X an element from group VIa, selected from sulfur, selenium and tellurium, M a metal or a metalloid, 0 a halogen radical , a is an integer from 0 to 3 inclusive, b is an integer from 0 to 2 ei Finally, c is an integer 0 or 1, where the sum of a + boc is a value of 3 or the valence of X, a = ef, f = valence of M and an integer from 2 to 7 inclusive. e # f and is an integer with a value of up to 8.

Remainders R are z. B. C (6-13) -aromatic hydrocarbon radicals, such as phenyl, tolyl, naphthyl, anthryl, and those radicals substituted with up to 1 to 4 monovalent radicals such as C (1-8) -alkoxy, C (1-8) -Alkyl, nitro, chlorine, hydroxy, etc., arylacyl radicals such as benzyl, phenylacyl, etc., aromatic heterocyclic radicals such as pyridyl, furfuryl, etc. R1 includes C alkyl and substituted alkyl such as (1-8) -C2H4OCH3 , -CH2COOC2H5, -CH2COCH3 etc. R @ radicals include structures such as Complex anions corresponding to [MQe] - (ef) of the formula are z. B.

BF4-, PF6-, AsF6-, SbF6-, FeCl4-, SnCl6--, SbCl6-, BiCl5--, AlF6-3, GaCl4-, InF4-, TiF6-, ZrF6-, etc., where M is a transition metal such as Sb, Fe, Sn, Bi, Al, Ga, In, Ti, Zr, Sc, V, Cr, Mn, Cs, rare earths such as lanthanides, e.g. B. Ce, Pr, Nd, etc., actinides such as T @, Pa, U, Np etc., and metalloids such as B, P, As etc. is.

Group UIa onium salts corresponding to the formula are, for. B.

Aromatic sulfonium salts are known and recognized in the art and in U.S. Patents 4,173,551, 4,026,705, 4,058,401 and 4,090,936, supra mentioned, described. The aromatic sulfonium complex preferred here as a photo starter is triphenylsulfonium hexafluoroantimonate.

The photocurable agents to be used in the present invention can a surfactant, such as a fluorocarbon surfactant, to improve the Coating of the visible light transmitting plate material is added to increased adhesion between the intermediate layer and the outer panels after the To promote hardening The photohardening of the agent occurs when irradiated by any A radiation source emitting actinic radiation of a wavelength in the UV spectral range a. Suitable sources of radiation include mercury, xenon, carbon arc and Tungsten wire lamps, Sunlight etc. The exposure times can Contribute less than about 1 second to 90 minutes or more, depending on the amounts the special epoxy material, organic polymer and aromatic Kemplex salt, which are currently being used and, depending on the radiation, all and that Distance between the source and the thickness of the intermediate layer to be adhered. The means can also be hardened by irradiation with electrons. One of the main advantages the electron irradiation is that the means travel at a higher speed za know to be cured as lit actinic radiation by irradiating.

The hardening is a triggered reaction, i. i.e. when the decay of the aromatic complex salt once by irradiating with a radiation source has started, the curing reaction continues even after the radiation source has been removed. The application of thermal energy during or after irradiation generally accelerates the hardening reaction, and even a moderate increase in temperature can greatly accelerate the curing speed.

The amount of aromatic used in the agents according to the invention Complex salt photoinitiator is about 0.1 to 20 parts by weight, preferably about 0.5 up to 2.0 parts by weight of the total agent. Generally speaking, the cure rate increases with increasing amounts of complex salt for a given exposure or irradiation. The hardening rate also decreases with increasing light intensity or electron dosage to.

The photocurable agents of the present invention are prepared by mixing them together under "safe light" conditions; d. H. non-actinic, the aromatic complex salt with the organic material, d. H. Epoxy plus organic polymer. Solvent-free agents are obtained by dissolving the aromatic complex salt in the organic material with or produced without the use of mild heating.

Although in the present application the term safety glass laminates has been used, the layers permeable to visible light can be made of Plate material made of any desired material zein, e.g. B. off Glass, poly (bisphenol A carbonate) or poly (methyl methacrylate).

Are the photocured agents for use in the present invention once photo-cured, they develop remarkable adhesion to almost any surface.

The new, improved process for the production of impact-resistant laminates according to the invention comprises a minimum of steps at low cost compared with conventional methods.

The epoxy-containing organic material and the compatible organic Polymers are mixed thoroughly into a solution.

If the polymer is present with a solvent, the solvent becomes by heating the solution of the epoxy and the polymer to about 68 to 80 ° C and Removal of solvent under vacuum.

When the epoxy polymer solution has cooled, the aromatic one becomes Sulphonium complex salt photoinitiator added. The solution is then warmed gently and stirred until the photoinitiator is solvated. A surfactant, such as a fluorocarbon surfactant, can be mixed into the solution at this point, if desired, with which the preparation of the photocurable agent is completed.

At least two layers of visible light transmitting plate material are selected and a calibrating amount of the photocurable agent between they are brought to the main surfaces of each layer to make a soft laminate material to build. The 100% solids photocurable compositions can have such viscosities have that the interposition of the agent z. B. by framing the outer edges the visible Light transmitting layers to form a shape into which the photocurable agent can be poured, or a lot the photocurable agent can be applied to one of the layers, the other layer positioned and the two layers pressed together to form the photohardenable To distribute funds in between. In any case, care should be taken to avoid the Formation of air bubbles between the photocurable agent and each layer of the To prevent plate material. The soft laminate thus formed then becomes one Source of actinic radiation or electron beam radiation for a sufficiently long time exposed to trigger the photocuring reaction. Has photohardened once started, the reaction can proceed until it is practically complete. The accruing solid, visible light transmitting laminate exhibits improved splinter resistance over an enlarged temperature range. That formed from the photocurable agent Plastic intermediate layer adheres strongly to each of the adjacent translucent Layers of what made the improved laminates for use as safety glass windshields for motor vehicles or other construction or glazing purposes makes where Impact and splinter resistance are desirable.

The following example serves to better illustrate the invention.

Example In the absence of actinic radiation, a photocurable Means made from the following components: Materials parts by weight ERL 4221 G '50.0 Rucoflex 1028-210S2 50.0 UVE 10143 2.1 FC 1714 1.0 103.1 1. 3,4-Epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate (Union Carbide) 2. Polyester made from neopentyl glycol and adipic acid with hydroxyl end groups (Hooker Chemical Company) 3. 50% (C6H5) 3S SbF6 in propylene carbonate (General Electric) 4. Fluorocarbon surfactant (3M Company).

ERL 4221 and Rucoflex 1028-210 are mixed. The WE 1014 is added and stir the solution and heat gently until the WE 1014 is solvated. That Surfactant FC 171 is then added and the agent stirred until thoroughly mixed is. The resulting photo-curable agent is placed between two previously cleaned glass plates by applying the agent to the first glass plate and counter-pressing the second Plate against the first plate to distribute the agent evenly between them forming an uncured glass composite about 0.25 mm (0.01 inch) thick brought.

The soft, uncured laminate becomes UV light near a 300 W / inch medium pressure mercury vapor lamp exposed approximately 12.7 cm (5 inches) from the lamp for 20 seconds. The through the The emergency curing reaction started by UV radiation can continue for about 60 minutes. The result is a hard, impact-resistant laminate that allows visible light to pass through.

It will be seen that the invention is new and improved Process for the production of impact-resistant, visible light-transmitting laminates in fewer steps and at lower cost.

The disclosure contents of the above-mentioned patents are by incorporated by reference in the present application.

Although the invention with reference to a preferred embodiment has been described, it is obvious that modifications and changes from Expert can be made. For example, the epoxy portion of the agent partially replaced by poly (vinyl butyral). All such modifications lie within the intended scope of the invention as defined by the claims.

Claims (12)

Claims 1. A method for producing a shock-resistant, for visible light permeable laminate, therefore not marked, that (a) at least two layers of sheet material transparent to visible light be presented, (bJ between the adjacent flake surfaces of each pair a photocurable adhesive layer comprising an epoxy prepolymer is applied to the layers and an effective amount of an aromatic complex salt photoinitiator is selected among an onium salt of a group Va element, an onium salt of an element of group VIa and an aromatic halonium salt, c) the adhesive layer a radiation source is sufficient to initiate photocuring of the adhesive layer is suspended; and (d) photocuring continues practically to completion will. 2. The method according to claim 1, characterized in 9 e k e n n z e i c h -n e t that it is made of glass for visible 3. The method according to claim 1, due to the fact that it is made from poly (bisphenol-A-carbonate) best: Ehenden, for visible light permeable plates is carried out. 4. The method according to claim 1, characterized in that g e k e n n z e i c h -n e t that it is made of poly (methyl methacrylate) for visible Light-permeable plates are passed through. 5. The method according to claim 1, characterized in that g e k e n n z e i c h -n e t that at least one layer of the visible light transmissive plate material Glass and at least one other layer of the sheet material transparent to visible light Poly (bisphenol A carbonate> is. 6. The method according to claim 1, characterized in that g e k e n n z e i c h -n e t that at least one of the layers of visible light transmissive plate material Glass and at least one other layer of the sheet material which is transparent to the sight Is poly (methyl methacrylate). 7. The method according to claim 1, characterized in that g e k e n n z e i c h -n e t that it comes with a layer of adhesive that is also an organic polymer that is not epoxy Prepolymer is, comprises, is carried out. 8. The method according to claim 1, characterized in that g e k e n n z e i c h -n e t that it contains an epoxy prepolymer, the 3,4-EpOxyCyclohexylmethyl-3,4-epoxycyclohexanecarboxylate includes, is carried out. 9. The method according to claim 7, characterized in that g e k e n n z e i c h -n e t that another organic polymer is a poly (neopentyl glycol adipate) with hydroxyl end groups is used. 10 The method according to claim 1 @ thereby o e k e n n z e i c h -n e t that the aromatic complex salt photoinitiator is a light-decomposing aromatic Onium salt of a Group VIa element, which is used to effect the curing of epoxy resin can, when exposed to radiant energy, being the aromatic Onium salt has the formula [(R) a (R1) b (R2) cX] d + [MQe] - (e-f) nat, where R is a monovalent aromatic organic rust, R1 a monovalent organic aliphatic residue, selected from alkyl, cycloalkyl and substituted alkyl, R2 is a polyvalent one organic radical that forms a heterocyclic or condensed ring structure, selected from aliphatic radicals and aromatic radicals, X is an element of Group VIa, selected from sulfur, selenium and tellurium, M a metal or methalloid, Q is a halogen radical, a is an integer from 0 to 3 inclusive, b is an integer from 0 to 2 inclusive, c is an integer 0 or 1, the sum of a + b + c is a value of 3 or the valency of X, d = e -f = valency of M and an integer from 2 to 7 inclusive, e = f and an integer with a Value of up to 8. 11. The method according to claim 1, characterized in that g e k e n n z e i c h -n e t that as an aromatic group VIa onium complex salt photoinitiator triphenylsulfonium hexafluoroantimonate is used. 12. Laminate, which is not shown the method according to one or more of claims 1 to 11 has been obtained.