JPH0678515B2 - Solvent-free hot melt-polyurethane adhesive composition - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a low-viscosity reactive urethane-hot melt adhesive composition having improved cohesive and adhesive strength by adding a low molecular weight acrylic resin. According to the present invention, an acrylic monomer is polymerized into the non-isocyanate component of the polyurethane-prepolymer and the component is reacted with a suitable isocyanate functional group to add a plasticizer or tackifier. A hot melt adhesive composition having a suitable coating viscosity is obtained without the need to do so.

[0002]

2. Description of the Prior Art Hot melt adhesives have a solids content of 100% which does not contain or need any solvent. Although it is a solid at room temperature, it melts to a liquid or fluid state when heated and is applied to the substrate in that state. Upon cooling, the adhesive reverts to the solid state and adhesive strength is obtained. In this regard, hot melt adhesives differ from other types of adhesives which achieve a solid state by evaporation or removal of solvent or by polymerization.

To obtain the required physical properties, many hot melt adhesives are prepared with thermoplastic materials that are melted and applied at elevated temperatures and that bond rapidly upon cooling.

Also typically, these thermoplastic properties are heat sensitive and result in joints which are lost under mild heat loading.

Hot melt adhesive compositions applied in the molten state solidify on cooling and subsequent curing by chemical crosslinking reactions have been prepared using special thermosetting materials such as polyurethane. These hot-melt materials show excellent heat resistance, but they do not have much inherent strength, and before the crosslinking reaction is carried out, heavy balsam (hea
vy balsam) or grease. Furthermore, polyurethane-based hot melt adhesives lack adequate adhesion for many commercial substrates such as polyvinyl chloride film, Mylar ™ (a polyester film from DuPont) and aluminum. Attempts have been made to improve the initial bond strength of polyurethane-hot melt adhesives by the addition of certain thermoplastics as taught for example in US Pat. No. 3,931,077. This thermoplastic, however, is generally a high molecular weight material (ie, greater than about 100,000), the addition of which clearly increases the coating viscosity of the adhesive and lowers it sufficiently to facilitate application. Therefore, it is necessary to add a plasticizer or a tackifier separately. Although the viscosity of the prepared adhesive in the hot state decreases, the addition of relatively large amounts of these plasticizing and tackifying components affects the adhesive properties of polyurethane-hot melt adhesives, especially bonding. It has a serious effect on the storage of objects.

[0006]

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an improved polyurethane hot melt which exhibits excellent initial adhesion to an extremely wide range of substrates and is heat resistant after storage of the joint. An object is to provide an adhesive composition.

[0007]

Means for Solving the Problems The present inventor has 1) mixed 2 to 90% by weight of an active hydrogen-free ethylenically unsaturated monomer with 10 to 98% by weight of a polyol, and 2) The mixture of 1) is polymerized by a radical polymerization method using a chain transfer agent to give a low molecular weight polymer, 3) polyisocyanate sufficient to obtain a desired isocyanate content and an isocyanate index is added, and a condensation polymerization method is used. A low molecular weight polymer of an ethylenically saturated resin, produced by polymerizing, comprises a polyurethane prepolymer containing terminal isocyanate groups, wherein the polyurethane prepolymer containing terminal isocyanate groups contains 0.25 to 15% of isocyanate. Room Temperature Solid Solvent-Free Polyurethane with Content and Isocyanate Index Greater than 1 and Not Greater than about 2-Hot Melts The adhesive composition can be easily applied without the need for additional scavenging tackifiers or plasticizers and has improved initial cohesive strength as well as improved post-storage strength of the cured joint. I found that. Furthermore, this adhesive is made of polyvinyl chloride, Myler (DuPo
nt polyester-film) and a wide range of substrates, including difficult-to-bond substrates such as aluminum, exhibiting the above-described improved properties.

The composition of the present invention comprises polymerizing an ethylenically unsaturated monomer in a polyol using a radical polymerization method,
It is then prepared by polymerizing the isocyanate component with this mixture using conventional condensation polymerization techniques. The latter polymerization method is advantageous for good control of the molecular weight (determined by the intrinsic viscosity) of the resulting vinyl polymer,
In short, a polymer is produced which is free of unwanted impurities. In addition, the reduction in the number of steps and composition components and elimination of intermediate packaging and storage results in significant cost savings.

Any radically polymerizable, active hydrogen-free ethylenically unsaturated monomer can be used in the present invention. Many of the customarily used are acrylic acid- or methacrylic acid-C ₁ -C ₁₂ -esters, but methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, n-propyl- or isopropyl acrylate and the corresponding methacrylates. Not limited to. Mixtures of compatible (meth) acrylate monomers can also be used. Such mixtures, including mixtures of butyl-acrylate and methyl-acrylate, are well known in the art. Additional ethylenically unsaturated monomers such as vinyl esters (e.g. vinyl acetate and vinyl propionate), vinyl ethers, fumarates, maleates, styrenes, acrylonitriles, ethylene, vinyl ethers, etc., as well as their copolymers. Can be used. The choice of individual monomers depends largely on the desired end use of the adhesive. For example, those skilled in the art know that selecting certain monomers results in pressure sensitive adhesives, while other monomers result in non-pressure sensitive adhesives. Similarly, suitable monomers can be selected for the preparation of structural adhesives, contact adhesives and the like.

Urethane-prepolymers are commonly used in the production of polyurethane hot melt adhesive compositions. In general, this prepolymer is produced by condensation polymerization of polyisocyanates and polyols, in particular diisocyanates and polyols. Polyols used include polyhydroxy ethers (substituted or unsubstituted polyalkylene ether glycols or polyhydroxy-polyalkylene ethers), polyhydroxy-polyesters,
Included are ethylene oxide- or propylene oxide-adducts of polyols and mono-substituted esters of glycols.

Any suitable organic polyisocyanate,
For example ethylene diisocyanate, ethylidene-diisocyanate, propylene-diisocyanate, butylene
-Diisocyanate, hexamethylene-diisocyanate, toluene-diisocyanate, cyclopentylene-
1,3-diisocyanate, cyclohexylene-1,4-diisocyanate, cyclohexylene-1,2-diisocyanate, 4,4′-diphenylmethane-diisocyanate, 2,2,
-Diphenylpropane-4,4'-diisocyanate, p-phenylene-diisocyanate, m-phenylene-diisocyanate, xylylene-diisocyanate, 1,4-naphthylene-diisocyanate, 1,5-naphthylene-diisocyanate, diphenyl-4,4'- Diisocyanate, azobenzene-4,4'-diisocyanate, diphenylsulfone-4,
4'-diisocyanate, dichlorohexamethylene-diisocyanate, furflidene-diisocyanate, 1-chlorobenzene-2,4-diisocyanate, 4,4 ', 4 "-triisocyanate-triphenylmethane, 1,3,5-triisocyanate-benzene , 2,4,6-triisocyanate-toluene and 4,4'-dimethyldiphenylmethane-2,2 ', 5,5'
-Tetraisocyanate or the like can be used.

The polyisocyanate component and the polyol component are mixed in proportions such that a urethane prepolymer having an isocyanate content of about 0.25 to about 15%, especially about 10% is obtained. Furthermore, the ratio of isocyanate equivalent and hydroxyl equivalent
(Known as the Isocyanate Index) should be greater than 1 but not greater than about 2. When maintaining a low isocyanate index, the level of free isocyanate content in the final hot melt adhesive composition is about
It can be lower than 4%, especially lower than 1%.
It has been found that the presence of large amounts of free isocyanate has a significant effect on the preparation of hot melt adhesives, as poisons are released when the adhesive is heated to the application temperature. Further, a larger amount of free isocyanate causes a decrease in viscosity and also a decrease in initial bonding strength of the adhesive. The exact amount of polyisocyanate used in the polymerization depends on the equivalent weight of the polyol, the amount of polyol and the particular polyisocyanate used. Generally, the amount of polyisocyanate required to achieve the above isocyanate content is from about 5% to about 55% of the final prepolymer.
Fluctuates in%.

According to the broadest scope of this invention, ethylenically unsaturated monomers can be polymerized using conventional radical polymerization techniques which result in relatively low molecular weights. For purposes of this invention, low molecular weight means a molecular weight in the range of about 10,000 to 30,000. This low molecular weight can be obtained by carefully monitoring and controlling the reaction conditions and generally by carrying out the reaction in the presence of a chain transfer agent such as dodecyl mercaptan. The correlation between intrinsic viscosity and molecular weight is known, and the inventor generally polymerizes monomers to an intrinsic viscosity of 0.1-0.4 (measured in a 9: 1 mixture of tetrahydrofuran and alcohol). Have been found to be particularly advantageous for use in the present invention. The resulting hot melt adhesive can be applied in the molten state to the substrates to be joined using techniques known to those skilled in the art. Urethane-based hot-melt adhesives take time to cure due to atmospheric humidity and form a crosslinked network.

According to one method for preparing the urethane-prepolymers of the present invention, the ethylenically unsaturated monomer is mixed with 10-98 wt% polyol in an amount of about 2-90 wt% and Polymerization using a conventional radical polymerization method in the presence of a chain transfer agent such as dodecyl mercaptan gives a low molecular weight polymer dissolved in a polyol. Following the polymerization of the ethylenically unsaturated monomers, the polyisocyanate and any additional components required for the urethane-prepolymer forming reaction are added and the reaction is carried out using conventional condensation polymerization techniques. In this way, the resulting prepolymer containing terminal isocyanate groups contains about 5-90% by weight of the urethane-prepolymer and 95-10% by weight of the low molecular weight polymer and can be applied to the substrate in the melt. It can then be cured over time in atmospheric humidity to form the above reaction curable hot melt adhesive which forms a crosslinked network.

As stated above, the resulting hot melt adhesive, which is solid at room temperature, has 3,000 to 50,000 cps (135
Approximately 1,500 to 25,000 cps at ℃ and 10,000 to approximately 10 at 108 ℃
The viscosity is suitable for application in the range (corresponding to 0,000 cps) and therefore no tackifiers and / or plasticizers are needed to obtain an appropriate application viscosity. However, it is noted that small amounts of tackifiers or plasticizers may be added so that they are present to the extent that they do not impair the desired adhesive properties.

The adhesive not only crosslinks to form a strong heat resistant bond, but also exhibits high initial bond strength and cohesive strength, so that the bonded structure is already easy to handle even before curing. And can be entrusted to subsequent processing steps. It is readily compatible with a wide range of applications where hot melt adhesives are commonly used.
High degree of heat resistance as encountered during processing or sterilization processes, including but not limited to lamination, bookbinding, labeling of bottles and bags, automobile interior assembly, manufacturing of nonwoven products for medical applications, etc. It is suitable for use in applications that require

It is hypothesized that these excellent properties are due, in part, to the formation of semi-inner- and inner-penetrating networks and in some cases the formation of graft copolymers. A semi-interpenetrated network will be obtained when a urethane-prepolymer (thermosetting) is used together with a crosslinkable group-free radically polymerizable polymer (thermoplastic). If the radically polymerized polymer contains crosslinkable groups, a fully infiltrated network will be obtained. Grafting also occurs with certain urethane-prepolymer components, such as urethane-prepolymer components containing carbon atoms having tertiary hydrogen atoms. Such tertiary hydrogen atom is a potential grafting position for acrylic or vinylic monomers.

[0018]

The invention is explained in more detail by the following examples, which are advantageous embodiments. However, these examples are provided for illustrative purposes only and, unless otherwise stated, do not limit the scope of the invention.

Example I A 1 liter reactor was equipped with a condenser, a gas inlet tube, a tube for slow addition, a thermometer, a stirrer and heating / cooling equipment. Each reaction component is as follows: 1. Polypropylene glycol (1,000 molar weight) 275.8g 2. 1,6-hexanediol, neopentyl glycol adipate (molecular weight 3,000) 88.9g 3. 1,6-hexanediol, neo Pentyl glycol adipate (Molecular weight 1,000) 29.3g 4. Butyl methacrylate 17.8g 5. Butyl methacrylate 94.1g 6. Methyl methacrylate 9.4g 7. Methyl methacrylate 53.6g 8. Dodecyl mercaptan 0.68g 9. Benzoyl-peroxide 1.7g 10. Benzoyl peroxide 0.6g 11. Methylene-bisphenyl-diisocyanate 131.1g The reactor is purged with dry nitrogen gas and a slow stream of dry nitrogen is introduced below the liquid during the reaction to bubble. 1, 2,
The ingredients labeled 3, 4, 6, 8 and 9 are added to the reactor and the temperature is raised to 80 ° C. After 1/2 hour at 80 ° C., ingredients 5 and 7 are added uniformly over 1 hour. The reaction is maintained at 80 ° C. for a further 3 hours, at which time 10 ingredients are added. The reaction was continued at 80 ° C for another 2 hours and
Add 11 ingredients. Then raise the temperature to 100 ° C and
Hold for 3 hours. At this point a vacuum of 120 mm to 130 mm is charged to the reactor for 20 to 30 minutes and the reaction is poured hot from the flask. Properties Methacrylate polymer (%) 25% Ratio of butyl methacrylate and methyl methacrylate 64/36 Urethane-prepolymer (%) 75% Isocyanate groups (%) 1.9% Viscosity at 100 ℃ 64,000cps Viscosity at 120 ℃ 25,250cps Viscosity at room temperature Solids Intrinsic viscosity in tetrahydrofuran / ethanol (9/1) 0.18 Color Water white to very slight amber Clear Transparent to very slightly cloudy Urethane-prepolymer molecular weight calculated 3315 Isocyanate Index 1.6 Example II This experiment was carried out as an alternative way to do so by reducing the molecular weight of the methacrylate resin, as in Example I where the viscosity of the system was reduced by reducing the molecular weight of the urethane-prepolymer. To do. All factors are identical except for the following: Component A B Butyl methacrylate 18.0 g 18.0 g butyl methacrylate 102.0 g 102.0 g methyl methacrylate 10.1 g 10.1 g component (trailing) A B Methyl methacrylate 57.4 g 57.4 g dodecyl mercaptan 0.63 g 0.72 g benzyl peroxide 1.8 g 1.8 g methylene - bis phenyl 168.6g 168.6g - diisocyanate properties: a B methacrylate polymer (%) ratio of 25% to 25% butyl methacrylate and methyl methacrylate 64 to 36 64 to 36 (%) Urethane-prepolymer (%) 75% 75% Isocyanate groups (%) 3.1% 3.3% Viscosity at 100 ℃ 53,000cps 51,000cps Viscosity at 120 ℃ Not measured 7,062cps Viscosity at room temperature Solid Solid THF / Ethanol (9 / 1) Intrinsic viscosity in 0.18 0.15 color Whiteness of water to very slight amber transparency Clear to very slight turbidity Calculated molecular weight of urethane-prepolymer 2032 3315 b Cyanate index 2.0 2.0 Example II I (Reference Example) This example of 70% polypropylene glycol and (molecular weight of 1,000) 30%, sufficient methylene to the NCO- content of 2% in the prepolymer - bis Disclosed is a urethane prepolymer composed of 1,6-hexanediol-neopentylglycol adipate-diol (molecular weight 2,000) containing phenyl-diisocyanate. Each component Propylene glycol (Molecular weight 1,000) 350.0 1,6-Hexanediol-Neopentyl glycol adipate-150.0 Diol (Molecular weight 2,000) Methylene-bisphenyl-diisocyanate 166.4 Operation Cooler, gas inlet pipe, thermometer in a 1-liter reactor , Equipped with stirrer and heating / cooling equipment. The reactor is purged with dry nitrogen gas and a slow stream of dry nitrogen is passed through the reaction vessel. The polyol is added to the reactor and the temperature rises to 80 ° C. At this point diisocyanate is added, the reaction mixture is heated to 100 ° C. and maintained at this temperature for 4 hours. After a heating time of 4 hours, the reaction mixture is poured out of the reactor.

The properties of the urethane-prepolymer are as follows: Isocyanate groups (%) 2.3% Viscosity at 100 ° C 3,200 cps Viscosity at room temperature 80,000 cps Color Very slight amber Transparency Transparent Isocyanate index 1.6 IV (Comparative Example) This example shows that a U.S. Pat.
It demonstrates a hot melt adhesive according to 3,931,077.

Prepolymer of Example III 60 CRL 715 (5 copolymer consisting of 35% n-butyl acrylate and 65% ethylene: manufacturer USI: melt index 70) PRL-300 (softening point at 108 ° C. Terpene-phenolic resin with: Manufacturer 35 Reichhold Chemical Urethane-prepolymer is placed in a three-necked flask, heated to 167 ° F under a dry nitrogen atmosphere and added with two additional ingredients. Then, the mixture is stirred under a nitrogen atmosphere until dissolved.
This adhesive is referred to as IVA.

A second hot melt adhesive (designated IVB) was prepared as described above with 10 parts of Exxon EX 170 (composed of 25% vinyl acetate and 75% ethylene with a melting index of 2,400). Prepared using 15 parts of PRL-300 and 65 parts of the urethane-prepolymer of Example III. Tests The following series of tests demonstrates the properties of the adhesives of the invention and the extent of their effect. Cured film tensile strength and elongation: This test
The strength and elasticity of the film are measured. Tensile strength and elongation relate to the utility of the material as an adhesive. In general, materials with high tensile strength and suitable elongation exhibit better adhesion behavior than materials with weaker one or both properties.

In this test, the film is about 3-5 m
Casting is performed from the molten state on the low energy surface of the il. (This range of films should be used as a relatively heavy film that develops excessive voids upon cooling.) This film is used at a constant room temperature (22
It cures by exposing it to an atmosphere of 50% humidity (° C). Adhesion test samples were prepared using various flexible substrates, 1.0 mil of hot melt adhesive was applied to the substrates and laminated directly to a 3/8 "particle board, the laminate being approximately 5 psi. 10 by pressure
Manufactured by subjecting to cold compression for minutes. All samples are allowed to cure or crosslink for 1 week. These are then subjected to a 90 ° peel test with a pull rate of 12 inch per minute. Heat resistance: Most hot melt adhesives are thermoplastic 8
Deform or flow when subjected to temperatures above 2 ° C. The inventor has devised a series of high temperature shear tests to measure resistance to flow or deformation at elevated temperatures up to 175 ° C.

In this test, a 3/8 "particle board coated with 1 mil of adhesive is used with 5 mils of bare aluminum-foil overlap stripping. All samples are cured for a week. A sample of this is placed in a circulating air oven at a load of 1 kg per square inch at 108 ° C. They are left at this temperature for 15 minutes, then the temperature is raised to 120 ° C and observed for 15 minutes, The temperature is then again raised at regular intervals until delamination is observed.Green Strength This test measures the bond immediately after application bonding, which tests the strength of the uncured adhesive before curing. Sufficient green strength is essential to hold the substrates together when stacked, while curing proceeds with atmospheric humidity. Bonding strength and hardness Speed is very important for the step of previously assembled or or laminated to cure sufficiently.

In this test, an adhesive sample in the molten state at 120 ° C. is applied to a 2 mil mylar film at exactly 1.0 mil thickness and directly sandwiched on a 5 mil aluminum foil. The resulting laminate of mylar / adhesive / foil is then peeled off directly and after the indicated time with an Instron tester at 12 inch / min.

Comparative Example of Viscosity at [0026] 120 ° C., viscosity (Thermosel) I (Example) in Comparative Example 120 ℃ 11,625 cps IIB (Example) 5,500 cps III (Example) 1,138 cps IVA (Comparative Example) 9,000 cps IVB (Comparative example) 5,000 cps Tensile strength / elongation ratio comparison Example, Comparative example Ultimate strength elongation (% ) I (Example) 1,350psi 460% IIB (Example) 3,250psi 440% III (Example) 667psi 440% IVA (Comparative) 960psi 520% IVB (Comparative) 200psi 1400% Low tensile strength in Examples III and IV and Examples I and II of the present invention show increased tensile strength with good elongation. ing. In addition, Example II, which has a high NCO content, exhibits high strength.

The white aluminum foil Iler like vinyl color vinyl I (Example) raised wood grain pattern 4mil Ma 6mil bare 2mil adhesive test results ^{5mil 6.5lbs * 4.2lbs * 5.5lbs * 4.5lbs} IIA ( Embodiment Example) 5.5lbs ^* 1.5lbs 6.5lbs ^* 5.5lbs ^* III (Example) 1.7lbs 1.8lbs 6.6lbs ^* 5.2lbs IVA (Comparative example) 7.6lbs ^* 0.4lbs 0.2lbs 4.0lbs ^* IVB (Comparative example) 6.7lbs ^* 0.9 lbs 7.0 lbs ^* 4.5 lbs ^* *: Fiber splitting Both Examples I and II provided excellent bonding to most substrates, and Example I was superior to all substrates including Mylar. Bring the bond. Bonding is performed on the fibers on the surface of the particle board. Example
II has a defective joint only to Mylar. Example II
I has a defective joint between foil and mylar. Comparative IVA is defective with Mylar and vinyl and Comparative IVB is defective with Mylar. Comparative example of heat resistance , 108 120 134 150 162 175 Comparative example ℃ ℃ ℃ ℃ ℃ ℃ ℃ I OK OK OK OK 13 minutes peeling-II (A / B) OK OK OK OK OK 8 hours OK OK OK 9 minutes Peeling off--IVA peeling off at 1 minute-----IVB Peeling off at 1 minute-----This test shows that the comparative examples IVA and IVB (prior art example) have poor heat resistance and Example I and It has been demonstrated that II has excellent heat resistance. Example II is a type with a high NCO content and exhibits the highest heat resistance. Comparison of bonding strength The above tests show that the hot melt adhesives of the present invention are superior in terms of bond strength and heat resistance after storage, in particular, to the acrylic-free prepolymer and those described in U.S. Pat.No. 3,831,077. It clearly shows that. The following examples embody variations of the best mode embodiment to demonstrate the invention in various respects. Example V The procedure of Example I is followed by adding 0.8 g of dodecyl-mercaptan.
Repeat except use in place of 0.68g. This modification lowers the molecular weight of the methacrylate copolymer portion of the product (indicated by a decrease in intrinsic viscosity) and hence the product viscosity.

Properties : Methacrylate polymer (%) 25% Ratio of butyl methacrylate and methyl methacrylate 64/36 Urethane-prepolymer (%) 75% Isocyanate groups (%) 2.0% Viscosity at 100 ° C 18,000cps at room temperature Viscosity Solids Intrinsic viscosity in tetrahydrofuran / ethanol (9/1) 0.15 Color Water white to very little amber Clear Transparency to very little cloudiness Isocyanate Index 1.6 Example VI This experiment was carried out using dodecyl-mercaptan. It is carried out as in Example I except that the chain transfer agent is reduced to 0.54 g in order to increase the molecular weight of the methacrylate polymer. Therefore, the viscosity is increased to be comparable to that of Example II.

The properties are as follows: Methacrylate polymer (%) 25% Ratio of butyl methacrylate to methyl methacrylate 64/36 Urethane-prepolymer (%) 75% Isocyanate groups (%) 3.0% at 100 ° C Viscosity 72,000 cps Viscosity at 120 ℃ 16,250 cps Viscosity at room temperature Intrinsic viscosity in solid THF / ethanol (9/1) 0.15 Color Water white to very slight amber transparency Clear to very slight cloudiness Isocyanate Index 1.6 Example VII This example is a modification of Example I in the following respects: 1) The ratio of methacrylate polymer to urethane-prepolymer is changed from 25/75 to 30/70. 2) Change the ratio of butyl methacrylate to methyl methacrylate from 64/36 to 80/20. 3) Change the urethane-prepolymer composition from polypropylene glycol, 1,6-hexanediol, neopentyl glycol-adipate-methylene-bisphenyl diisocyanate to propylene glycol-methylene-bisphenyl diisocyanate.

This example is referred to as Example I using the following amounts:
The same is done.Each component Polypropylene glycol (1,000 molecular weight) 300.3 g Butyl methacrylate 23.0 g Butyl methacrylate 130.6 g Methyl methacrylate 5.8 g Methyl methacrylate 32.6 g Dodecyl mercaptan 0.3 g Benzoyl-peroxide 1.9 g Benzoyl peroxide 0.6 g Methylene-bisphenyl-diisocyanate 147.8 g Properties are as follows: Methacrylate polymer (%) 30.0% Ratio of butyl methacrylate and methyl methacrylate 80/20 Urethane-prepolymer (%) 70.0% Isocyanate groups (%) 3.9% Viscosity at 100 ° C 104,000cps Viscosity at room temperature Solid Intrinsic viscosity in THF / Ethanol (9/1) 0.19 Color Whiteness of water Transparency Transparent to very slight turbidity Isocyanate index 2.0Example VIII This example was demonstrated using various acrylate monomers
is doing. This example uses the following ingredients to prepare Example I
Carry out in the same manner as.Each component Polypropylene glycol (1,000 molecular weight) 326.4 g Butyl methacrylate 150.0 g Dodecyl mercaptan 0.3 g Benzoyl-peroxide 2.0 g Methylene-bisphenyl-diisocyanate 122.8 gnature: Acrylate polymer (%) 25.0% Urethane-prepolymer (%) 75.0% Isocyanate groups (%) 1.7% Viscosity at 100 ° C 7,200 cps Viscosity at room temperature <2.8 × 10 THF / Ethanol (9/1) Intrinsic viscosity 0.15 Color Brown Transparent Opaque Isocyanate Index 1.5Example IX In this example methylene-bisphenyl-diisocyanate
Isocyanate was used in addition to the resin. This example is as follows
Was carried out as in Example I using the components of Prescription Polypropylene glycol (1,000 molecular weight) 275.7 g 1,6-hexanediol, neopentyl-adipatediol 118.2 g (molecular weight 2,000) Butyl methacrylate 17.8 g Butyl methacrylate 94.1 g Methyl methacrylate 9.1 g Methyl methacrylate 53.6 g Dodecyl mercaptan 0.68 g Benzoyl-peroxide 1.7 g Benzoyl-peroxide 0.6g Methylene-biscyclohexyl-diisocyanate 137.4g Dibutyltin dilaurate 0.08gnature: Methacrylate polymer (%) 25.0% Ratio of butyl methacrylate and methyl methacrylate 64/34 Urethane-prepolymer (%) 75.0% Isocyanate group (%) 2.2% Viscosity at 120 ° C 5,000cps (estimated) Viscosity at room temperature Intrinsic viscosity in solid THF / ethanol (9/1) 0.13 colors Whiteness of water Transparency Transparent Isocyanate index 1.6Example X In this example, a catalyst is added to accelerate the cure rate.
It This reaction is also carried out using the procedure of Example I.Prescription Polypropylene glycol (1,000 molecular weight) 275.7g 1,6-hexanediol, neopentyl-adipatediol (molecular weight 2,000) 118.2g Butyl methacrylate 17.8g Butyl methacrylate 94.1g Methyl methacrylate 9.4g Methyl methacrylate 53.6g Dodecyl mercaptan 0.68g Benzoyl-peroxide 1.7g Benzoyl-peroxide 0.6g Methylene-biscyclohexyl-diisocyanate 131.1g Dibutyltin dilaurate 0.30gnature: Methacrylate polymer (%) 25% Ratio of butyl methacrylate and methyl methacrylate 64/34 Urethane-prepolymer (%) 75% Isocyanate group (%) 1.9% Viscosity at 100 ℃ 84,000cps Viscosity at room temperature Solid THF / Intrinsic viscosity in ethanol (9/1) 0.17 color Whiteness of water or very slightly amber Clear Haze cloudiness Isocyanate index 1.6Example XI In this example, the acrylate copolymerizable monomer is
Example I is repeated. Each component and property are as follows
It is as below.Prescription Polypropylene glycol (1,000 molecular weight) 275.7g 1,6-hexanediol, neopentyl-adipatediol (molecular weight 2,000) 118.2g Styrene 174.9g Dodecyl mercaptan 0.68g Benzoyl-peroxide 1.7g Benzoyl-peroxide 0.6g Methylene-bisphenyl-diisocyanate 131.1gnature: Styrene polymer (%) 25% Urethane-prepolymer (%) 75% Isocyanate groups (%) 1.7% Viscosity at room temperature Solid THF / Intrinsic viscosity in ethanol (9/1) 0.23 Color Yellowish transparent Turbidity Isocyanate index 1.6Example XII Implemented by replacing acrylate copolymer with vinyl acetate
Repeat Example I. The ingredients and properties are as follows:
ItEach component Polypropylene glycol (1,000 molecular weight) 275.7 g 1,6-hexanediol, neopentyl-adipatediol (molecular weight 2,000) 118.2 g Vinyl acetate 174.9 g Dodecyl mercaptan 0.68 g Benzoyl-peroxide 1.7 g Benzoyl-peroxide 0.6 g Methylene-biscyclohexyl-diisocyanate 137.4 gnature: Vinyl acetate polymer (%) 25% Urethane-prepolymer (%) 75% Isocyanate group (%) 2.0% 121 ° C viscosity 1800cps Room temperature viscosity <4 × 10⁶cps Intrinsic viscosity in THF / ethanol (9/1) 0.15 colors Amber color Transparency Turbid Isocyanate index 1.6Example XIII Reference Example This example is a hot melt according to an embodiment of the present invention.
Add commercially available low molecular weight polymers to make adhesives
Prove the case. Elvacite 2013 is
64 with an intrinsic viscosity of 0.2 available from DuPont
% Butyl Methacrylate / 36% Methyl Methacrylate-
It is a polymer. Use this Elvasit immediately before use.
Dry under vacuum for 24 hours.Each component Polypropylene glycol (1,000 molecular weight) 472.9g 1,6-hexanediol, neopentyl-adipatediol (molecular weight 2,000) 202.7g Elvasit 2013 300.0g Methylene-bisphenyl-diisocyanate 224.9goperation : Polyol and Elvasit 2013 in reactor
Introduce and heat to 100 ° C until Elvasit is dissolved.
It At that point methylene-bisphenyl-diisocyanate
Is added and the reaction is carried out at 100 ° C. for 3 hours. Ten
After 3 hours at 0 ° C, the reaction mixture is left hot in the reactor.
Pouring out. This sample has the following properties:nature: Methyl acrylate polymer (%) 25% Urethane-prepolymer (%) 75% Isocyanate group (%) 2.0% Viscosity at 100 ℃ 86,000cps Viscosity at 120 ℃ 8,000cps Viscosity at room temperature Solid THF / ethanol (9 / 1) Intrinsic viscosity in 0.25 color White of water Transparency Transparent to very slightly cloudy Isocyanate index 1.6Test results Ultimate tensile strength 1,700 psi Elongation (%) 400% Viscosity stability at 120 ° C: First 8,000 cps After 8 hours 12,125 cps Bond strength (Foil / Mylar): Immediately 908g 1 hour 1025g 2 hours 1040g 3 hours 1100g 24 hours 1750g Adhesion Test (90 ℃ peel): Mylar 1.7 lbs 5 mil foil 5.5 lbs Wood grain vinyl 6.9 lbs White vinyl 5.7 lbs Heat resistance (2psi): 180 ℃ OK 120 ℃ OK 134 ℃ OK 150 ℃ OK 162 ℃ peel after 10 minutes Example XIV For the purpose of comparing initial (raw) strength properties, additional adhesive (1
~ 4) according to the present invention using the procedure described above.
To do. Five adhesives of US Pat. No. 3,968,089
Examples II, III, IV, V and IX (labeled 5-9 respectively)
Manufacturing).

The components of the raw materials used and their amounts (g) are shown in Table I below.

The intrinsic viscosity, the isocyanate index and the viscosity at room temperature are shown in Table II.

[0033] The following test methods are used to test the initial (green) strength performance of each adhesive. The test results are shown in Table III. Peel Test: A wood-patterned vinyl substrate is coated (directly or by transfer) with an adhesive heated to approximately 120 ° C to a thickness of 1.0 to 1.5 mil, with a 3/8 "thick particle board. ~
Compress at 5 lbs pressure for 5 seconds. The sample is peeled with a peel tester, eg, an Instron tester at a speed of 5 "/ min at an angle of 90 °. (Sample dimensions:
1/2 "width, 3-4" length). Immediately after compressing this sample
It peels off (that is, within 1 to 2 minutes). Lap shear : about 120 on 5 mil standard size aluminum
Apply adhesive (either directly or by transfer) heated to ℃ to a thickness of 2-3 mils. Compress the coated aluminum with a 3/8 "thick particle board for 3-5 minutes at a pressure of about 5 lbs. Samples at 0.2 inch / min in a tensile tester (eg Instron-tester). At an angle of 180 ° at (sample size = 1/2 "x 1/2" bonded area). Pull this sample immediately after compression (ie within 1-2 minutes).

Table III Adhesive Release (lbs / inch ) Lap Shearability (lbs / inch ) 1 4.2 to 4.4 31.5 2 4.0 to 4.0 18.2 3 1.0 to 1.1 9.3 4 1.4 to 1.7 15.1 5 No initial bonding No initial bonding 6 No initial bonding No initial bonding 7 No initial bonding No initial bonding 8 No initial bonding No initial bonding 9 No initial bonding Various initial modifications and variations are the embodiments of the present invention described above and defined in the claims. Obviously, it does not depart from the scope of the invention described and therefore it is not necessary to demonstrate all the inventions described in the specification and the above examples do not limit the invention.

[0035]

[Table 1]

[0036]

[Table 2]

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Claims (9)

[Claims] 1. The following steps: 1) mixing 2-90% by weight of an active hydrogen-free ethylenically unsaturated monomer with 10-98% by weight of a polyol 2) chaining the mixture of 1) above It is produced by polymerizing by a radical polymerization method using a transfer agent to obtain a low molecular weight polymer, and 3) adding a polyisocyanate sufficient to obtain a desired isocyanate content and an isocyanate index, and polymerizing by a condensation polymerization method. , A low molecular weight polymer of an ethylenically saturated resin is internally polymerized and comprises a terminal isocyanate group-containing polyurethane prepolymer, wherein the terminal isocyanate group-containing polyurethane prepolymer has an isocyanate content of 0.25 to 15% and greater than 1. And a room temperature solid, solvent-free polyurethane-hot melt adhesive composition having an isocyanate index no greater than about 2. 2. The ethylenically unsaturated monomer is acryl acid
Or methacrylic acid C ₁~ C₁₂ -Ester, vinyl aesthetic
Le and-ether, fumarate, maleate, styre
Amine, acrylonitrile, ethylene and mixtures thereof
Claim 1 selected from the group consisting of
Hot melt adhesive composition. 3. The hot melt adhesive composition according to claim 1, wherein the urethane-prepolymer is produced by condensation polymerization of diol and diisocyanate. 4. The hot melt adhesive composition according to claim 1, wherein the ethylenically unsaturated monomer is polymerized to an intrinsic viscosity of 0.1 to 0.4. 5. A polyalkylene-ether-glycol or polyhydroxy-polyalkylene ether in which a polyol is substituted or unsubstituted, a polyhydroxy-polyester, an ethylene oxide- or propylene oxide adduct of a polyol, and a mono-substituted ester of a glycol. The hot melt adhesive composition according to claim 1, which is selected from the group consisting of: 6. The polyisocyanate is ethylene diisocyanate, ethylidene-diisocyanate, propylene.
-Diisocyanate, butylene-diisocyanate, hexamethylene-diisocyanate, toluene-diisocyanate, cyclopentylene-1,3-diisocyanate,
Cyclohexylene-1,4-diisocyanate, cyclohexylene-1,2-diisocyanate, 4,4'-diphenylmethane-diisocyanate, 2,2, -diphenylpropane-4,
4'-diisocyanate, p-phenylene-diisocyanate, m-phenylene-diisocyanate, xylylene-diisocyanate, 1,4-naphthylene-diisocyanate,
1,5-naphthylene-diisocyanate, diphenyl-4,4'-
Diisocyanate, azobenzene-4,4'-diisocyanate, diphenylsulfone-4,4'-diisocyanate, dichlorohexamethylene-diisocyanate, furfuridene
-Diisocyanate, 1-chlorobenzene-2,4-diisocyanate, 4,4 ', 4 "-triisocyanate-triphenylmethane, 1,3,5-triisocyanate-benzene, 2,4,6-
A hot melt adhesive composition according to claim 1 selected from the group consisting of triisocyanate-toluene and 4,4'-dimethyldiphenylmethane-2,2 ', 5,5'-tetraisocyanate. 7. The hot melt adhesive composition according to claim 1, which has a free isocyanate content of less than 4%. 8. The hot melt adhesive composition according to claim 7, which has a free isocyanate content of less than 1%. 9. A mixture of 1) 2 to 90% by weight of an active hydrogen-free ethylenically unsaturated monomer and 10 to 98% by weight of a polyol. 2) The mixture of 1) above is used as a chain transfer agent. Polymerize to a low molecular weight polymer by radical polymerization, 3) add sufficient polyisocyanate to obtain an isocyanate content of 0.25 to 15% and an isocyanate index greater than 1 and less than about 2 and by a condensation polymerization method. A process for producing a solvent-free hot melt adhesive which is solid at room temperature and has a viscosity of 3,000 to 50,000 cps at 120 ° C in the absence of a polymerizing tackifier and / or plasticizer.