JP2003511541A - Adhesive containing linear and isotactic polymer - Google Patents

Abstract

  (57) [Summary] The present invention relates to an adhesive comprising a polymer material, wherein the structure of the polymer material contains an elastic amorphous area having a nanoscale size reinforced by self-aligned crystalline domains of nanocrystals.

Description

Detailed Description of the Invention

FIELD OF THE INVENTION The present invention relates to adhesives used, for example, in assembling articles. Specifically, the present invention relates to elastic adhesives.

BACKGROUND Adhesives, especially adhesives containing olefinic polymers, are well known in the art and enjoy widespread use throughout the industry. Typical areas of application for such adhesives include hygiene products, and in particular disposable absorbent products, packaging materials, automotive parts and the like.

Adhesives made from commonly used polyolefins such as PP, PE, PS, PIB have many useful properties. They are biocompatible and food compatible, chemically stable, inert, non-toxic materials. But,
Most of them have poor mechanical properties including insufficient strength / tear resistance, insufficient stretch / elasticity, etc.

Other adhesives, such as PU-based adhesives, are for example due to their elasticity. It has been widely used. However, PU adhesives cannot be used for many applications because they are polymerized from highly toxic monomeric isocyanates and thus their inherent toxicity due to residual monomer content. It has the drawback.

In the prior art, several approaches have been taken to provide elasticity to such adhesives. The most commonly used approach is based on altering the chemical structure of the polymer by introducing hinge-type connections / moieties in the polymer backbone. These side groups or side chains give the polymer backbone greater flexibility, prevent polymer crystallization, lower the glass transition temperature (Tg), and improve the elasticity of the resulting material. . Usually, the hinge group contains a heteroatom that imparts flexibility such as oxygen, nitrogen or chlorine located in the backbone or in bulky side groups. Another approach is the kneading of polymers by incorporating special plasticizers. However, both approaches require the introduction of heteroatoms in the molecule or in the bulk of the coating material.

A third approach proposed in the prior art to provide elastic properties to such adhesives is closer to the present invention and is a heterophase that reinforces the bulk material by forming a physical net. Is to use the formation of. To do this, block copolymerization of two or more distinct monomers is used to result in a polymer backbone containing blocks with different Tg's. This results in microphase separation in the bulk due to the formation of the reinforcing crystalline domains of one copolymer linked together by the flexible chains of the second copolymer.

[0007] In essence, conventional adhesives have a wide range of inherent drawbacks: insufficient strength / tear resistance, insufficient stretch / elasticity, not biocompatibility, food compatibility. Non-exclusive, including but not limited to, containing heteroatoms such as chlorine, and thus providing toxic residues when burned.

It is an object of the present invention to provide an adhesive that overcomes the drawbacks of prior art adhesives.

[0009]   It is a further object of the invention to provide an article that includes an elastic adhesive.

It is a further object of the present invention to provide a method for making the adhesive of the present invention.

SUMMARY OF THE INVENTION The present invention provides an article that includes a first element and a second element that is joined to the first element with an adhesive. The article is such that the adhesive is less than 60% [mm
mm] pentad concentration isotacticity is included in the polyolefinic homopolymer.

The present invention further provides a method for providing the previously described adhesive coating, the method comprising hot melt, spray, powder melt, extruded bead, liquid, solvent based, pressure sensitive and their. Applying an adhesive selected from the group consisting of combinations.

DETAILED DESCRIPTION OF THE INVENTION The present invention comprises an article comprising a first element and a second element joined to said first element using an elastic adhesive comprising a polyolefinic homopolymer. I will provide a.

The term “polyolefinic homopolymer” as used herein means a polyolefin that contains molecules of only one phase, all of which exhibit similar stereochemical configurations. In using this term, blends of atactic and isotactic polymers in which the two layers are polymerized simultaneously are excluded. The term homopolymer includes copolymers in which all molecules exhibit similar stereochemical configurations.

[0015] Polyolefin homopolymers of the present invention may comprise a linear isotactic polymers having a structure of one or several C ₃ having a C _{2 0} olefinic monomers, the polymer is 60% Having a [mmmm] pentad concentration of less than, preferably less than 50%, more preferably less than 40%, and most preferably less than 30%, and greater than 8%, preferably greater than 10%, more preferably 12%. It has a greater isotacticity of [mmmm] pentad concentration, and most preferably greater than 15%. Preferably the polyolefinic homopolymer is polypropylene.

The homotactic isotacticity may be reduced compared to prior art isotactic polypropylene due to the statistical distribution of steric errors in the polymer chain. The term "stereoscopic error" refers to a stereoscopic sequence characterized by a [mrrm] pentad. In this case, the central monomer has the opposite configuration as the other four monomers in the pentad. Therefore, [mrrm] in this polymer
The pentad concentration is the statistical value of p ² (1-p) ^{2 where} p = [m], and thus 1-p = [r], and p ⁴ = [mmmm]. Greater than probability. Preferably, the pentad concentration is at least [p (1-p)] ^q p (1-
p), wherein q is 0.8, more preferably q is 0.6, even more preferably q is 0.4, even more preferably q is 0.2, and Most preferably q is 0.1.

In some embodiments of homopolymers, and especially those in which crystallinity is reduced using a single steric error, a low content of atactic sequences is a property of the adhesives of the invention. Proved to be beneficial to. Preferably the [rmrm] pentad concentration is less than 6%, more preferably less than 5%, even more preferably less than 4%, even more preferably less than 3%, most preferably 2.5%.
Is less than.

In some embodiments of homopolymers, and especially those in which crystallinity is reduced using a single steric error, a low content of syndiotactic sequences reduces the adhesive of the present invention. Proved to be beneficial to the properties of. Preferably the [rrrr] pentad concentration is less than 6%, more preferably less than 5%, even more preferably less than 4%, even more preferably less than 3%, most preferably 2%.
． It is less than 5%.

Alternatively, the homopolymer of the invention may comprise an array of atactic and isotactic blocks of the polymer.

Preferably, the average molecular weight M _W of the polymer is greater than 100,000 g / mol, more preferably greater than 200,000 g / mol, even more preferably 25.
Greater than 0000 g / mol, even more preferably greater than 300,000 g / mol, and most preferably greater than 350,000 g / mol. Higher molecular weights are particularly beneficial when the elastic and tear resistance properties of the adhesive material are desired.

For some applications such as adhesion to polymers and mammalian tissues, it is preferred that the molecular weight is less than 200,000 g / mol, more preferably less than 175,000 g / mol and most preferably less than 150000 g / mol.

The glass transition temperature Tg is between −50 ° C. and 30 ° C. The glass transition temperature is preferably less than 10 ° C, more preferably less than 5 ° C, even more preferably less than 0 ° C,
Most preferably, it is less than -6 ° C. After heating the sample to 150 ° C. and subsequently cooling the polymer to −50 ° C., the melting temperature of the polymer is obtained.

Without wishing to be bound by this theory, polyolefinic polymers exhibit a semi-crystalline structure. The structure contains nanoscale sized elastic amorphous regions reinforced by self-aligned crystalline domains of the nanocrystal. The formation of brittle macrocrystalline materials from polymers is achieved by the introduction of defects in the polymer backbone. Isolated monomer units with opposite configurations have been used as defects or single steric errors.

Suitable polymers and methods for making such polymers are described in PCT patent application EP 99/02379, which is hereby incorporated by reference. Suitable catalyst combinations for the preparation of such polymers are described in PCT patent application EP 99/02378, which is hereby incorporated by reference. The method described in PCT patent application EP 99/02378 is preferably below 30 ° C, more preferably below 25 ° C, even more preferably below 20 ° C.
Most preferably carried out at temperatures below 15 ° C. to increase the molecular weight of the resulting polymer. To increase the molecular weight, the polymerization is preferably carried out in a liquid monomer such as liquid propene. If it is desired to increase the molecular weight, the catalyst is preferably used in combination with the boron activator mentioned in PCT patent application EP 99/02378.

Other suitable polymers and methods for making such polymers are described in International Application Publication WO 99/20664, which is incorporated herein by reference.

In the prior art, applying adhesives in forms such as hot melts, sprays, powder melts, extruded beads, liquids, solvent based, pressure sensitive, meltblown fibers and combinations thereof. A wide variety of suitable techniques are known for providing adhesive coatings, such as The aforementioned method for providing an adhesive coating comprises
All have the inherent advantages known to those of ordinary skill in the art. Therefore, one skilled in the art can select the appropriate method for providing the adhesive coating of the present invention, depending on the specific requirements of the particular application of the adhesive.

It has been found that the adhesives of the present invention can adhere to polished surfaces such as metal plates, PTFE coated surfaces, polymer surfaces and the like. The adhesive of the present invention is also suitable for adhesion to mammalian tissue such as epidermal tissue.

The adhesion between the two elements of the product of the invention is preferably at least 5 Newtons per centimeter, more preferably at least 10 N / cm, even more preferably 20 N / cm, most preferably 40 N / cm. Is adjusted. Of course, if a lower peel force is desired, the properties of the adhesive, such as its molecular weight, can be changed accordingly. Alternatively, the same peel force requirements apply when attaching the surfaces to each other. Peel forces are measured in terms of the specific surface area where they are used.

It was further found that the adhesive of the present invention only emits a relatively small amount of odor even in its molten state. In particular, it is possible to make the adhesives of the invention without the use of a solvent, and thus, in some embodiments of the invention, the adhesive does actually contain a solvent.

In some embodiments, and especially those with high molecular weight, the adhesives of the present invention are found to exhibit increased temperature stability as compared to prior art adhesives. It was This is due, in part, to the use of homopolymers in the adhesives of the present invention and, in part, to the high molecular weight of the homopolymers. The adhesive material of the present invention preferably has a melting point of at least 100 ° C, more preferably at least 110 ° C, more preferably at least 120 ° C, most preferably at least 130 ° C. The melting temperature of the polymer is obtained after heating the sample to 150 ° C and subsequently cooling the polymer to -50 ° C. If desired, higher melting points may be achieved by incorporating homopolymers with conventional isotactic polymers such as polypropylene.

Alternatively, and especially in embodiments where the adhesive has a relatively low molecular weight, a melting point of approximately 50 ° C. can be achieved. Such a melting point can be used to deactivate the adhesive where this is desired. Heating the adhesive to its melting point causes the adhesive to flow and can therefore be peeled with very low peel forces.

It has been found that, in addition to being elastic, the adhesive of the present invention is extensible. The stretchability of the adhesive with respect to its elastic behavior can be adjusted using the tacticity of the homopolymers of the invention. The adhesive material of the present invention is at least 500% of its initial length without tearing, more preferably at least 1000% of its initial length,
Even more preferably, it was found to be extendable to at least 1500% of the initial length, and most preferably at least 2000% of the initial length. In addition, the adhesive material of the present invention is preferably less than 300% of its initial length, preferably 200% of its initial length after being stretched to 500% of its initial length and held for 1 minute.
%, Most preferably less than 150% of its initial length within 10 minutes.
In addition, the adhesives of the present invention have been found to exhibit low compression set. The adhesive of the present invention is preferably at least 60% of its initial thickness, more preferably at least 70% of its initial thickness after compression to 50% of its initial thickness for 1 minute.
%, Even more preferably at least 80% of its initial thickness, even more preferably at least 90% of its initial thickness, and most preferably at least 95% of its initial thickness within 10 minutes. The compressibility of the adhesives of the present invention can be adjusted by increasing the tacticity of the homopolymer or by blending conventional isotactic polymers such as polypropylene and low tacticity homopolymers.

Without wishing to be bound by this theory, the rheological properties of the adhesives of the invention, namely the storage modulus or modulus G ′ and viscous modulus G ″, are
It is believed to exhibit the creep of the adhesive of the invention and the release / quick stick behavior of the adhesive of the invention during use, respectively. Low frequency (approximately 0.01 rad / s
To 1 rad / s) and high frequency G (100 rad / s to 1000 rad / s)
The'and G'values are believed to be related to the behavior of the adhesive during deposition and removal, respectively. Using a Rheometric Scientific RS-5 rheometer, for example, to measure G'and G "over a wide range of frequencies. It is well known in the art that this can be done. The measurements of G ′ and G ″ should be performed at the desired use temperature, ie room temperature of 25 ° C. for most applications or 37 ° C. for body related applications.

The adhesive of the present invention is preferably less than 30,000 Pa, more preferably 2,500.
Less than 0 Pa, even more preferably less than 20,000 Pa, most preferably 150.
It has a viscous modulus G "(1 rad / s) of less than 00 Pa. While not wishing to be bound by this theory, these values of G" (1 rad / s) indicate that the adhesive will adhere to the surface. It is believed to indicate that the adhesive does not flow out when it is run.

The adhesive of the present invention preferably has a viscous modulus G ″ (1 rad / s) of at least 500 Pa, more preferably at least 1000 Pa, even more preferably at least 1500 Pa, most preferably at least 2000 Pa. While not wishing to be bound, it is believed that these values of G ″ (1 rad / s) indicate that the adhesive can adapt to the morphology of the surface to which it is applied.

The adhesive of the present invention is preferably less than 30,000 Pa, more preferably 2000.
Less than 0 Pa, even more preferably less than 15,000 Pa, most preferably 100.
It has a viscous modulus G "(100 rad / s) of less than 00 Pa. Without wishing to be bound by this theory, these values of G" (100 rad / s) indicate that the adhesive has been removed from the surface. It is believed to indicate that the adhesive does not flow out when it is run.

The adhesives of the present invention preferably have a viscoelastic modulus G ″ (100 rad / s) of at least 1000 Pa, more preferably at least 2000 Pa, even more preferably at least 3000 Pa, most preferably at least 4000 Pa. While not wishing to be bound, it is believed that these values of G ″ (100 rad / s) indicate that the adhesive does not split upon removal from the surface.

The adhesive of the present invention is preferably less than 30,000 Pa, more preferably 2500.
Less than 0 Pa, even more preferably less than 20,000 Pa, most preferably 150.
It has a viscous modulus G '(1 rad / s) of less than 00 Pa. The adhesive of the present invention is preferably at least 500 Pa, more preferably at least 1000 Pa, even more preferably at least 1500 Pa, most preferably at least 2000 P.
It has a viscous modulus G '(1 rad / s) of a. Without wishing to be bound by this theory, it is believed that these values of G '(1 rad / s) indicate that the adhesive retains its elasticity when it is applied to the surface. To be

The adhesive of the present invention is preferably less than 30,000 Pa, more preferably 2,500.
Less than 0 Pa, even more preferably less than 20,000 Pa, most preferably 150.
It has a viscous modulus G '(100 rad / s) of less than 00 Pa. The adhesive of the present invention is
Preferably at least 2000 Pa, more preferably at least 3000 Pa,
Even more preferably at least 4000 Pa, most preferably at least 50
It has a viscoelastic modulus G '(100 rad / s) of 00 Pa. Without wishing to be bound by this theory, it is believed that these values of G '(100 rad / s) indicate that the adhesive retains its elasticity upon removal from the surface.

Preferably, the ratio of G ′ (1 rad / s) / G ″ (1 rad / s) is in the range of 1 to 30. This is the ratio between the application of the adhesive to the surface of the substrate, It is believed to exhibit the flow behavior of the inventive adhesive.

Of course, if different values of G ′ and G ″ are desired, the adhesive properties can be adjusted accordingly within the limits given above.

The adhesive according to the invention may be used as a building element in an article. Such articles include, but are not limited to, toys, furniture, clothing, shoes, sports equipment, complex structures such as buildings, cars, home appliances, and the like. With regard to the particular advantages of the polymers used for the articles of the invention, it is appropriate to apply the adhesive according to the invention as a building element in the above-mentioned and equivalent articles and to make any necessary modifications. It will be easy for the trader to identify.

The adhesives of the present invention are suitable for joining non-sticking polymer surfaces, for joining wood surfaces and for joining wood surfaces, for bonding Plexiglas and for bonding Plexiglas.

The adhesive allows the application in which the adhesive needs to be extensible, that is to say that the combined surfaces of the first and second elements make small movements relative to each other. Suitable for the intended use. For example, the adhesive of the present invention may be used as a binder resin in nonwoven web materials. The adhesive of the present invention will permit further processing of such nonwoven web materials (such as mechanical activation such as ring rolling).

The adhesive of the present invention may be activated by, for example, infrared rays, ultraviolet rays, electromagnetic radiation such as visible rays, ultrasonic waves and the like.

Additives such as those known in the art may be added to the adhesives of the present invention. For example, the addition of talc is suitable to modify the adhesive properties.

─────────────────────────────────────────────────── ─── Continued front page    (81) Designated countries EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, I T, LU, MC, NL, PT, SE), OA (BF, BJ , CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP (GH, GM, K E, LS, MW, MZ, SD, SL, SZ, TZ, UG , ZW), EA (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), AE, AG, AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, BZ, C A, CH, CN, CR, CU, CZ, DE, DK, DM , DZ, EE, ES, FI, GB, GD, GE, GH, GM, HR, HU, ID, IL, IN, IS, JP, K E, KG, KP, KR, KZ, LC, LK, LR, LS , LT, LU, LV, MA, MD, MG, MK, MN, MW, MX, MZ, NO, NZ, PL, PT, RO, R U, SD, SE, SG, SI, SK, SL, TJ, TM , TR, TT, TZ, UA, UG, US, UZ, VN, YU, ZA, ZW (72) Inventor Bernhard Riegel             Germany 89075 Ulm Johann-Stock             Carl-Veg 8 (72) Inventor Eudit Plushen             Germany 55129 Mainz Alfred             -Dublin Strasse 37 (72) Inventor Mike Oros             British TW 10 6 are             J Surrey Richmond Richmo             N'D Hill 122 Flat 3 F-term (reference) 4D075 CA03 CA12 DA04 DA06 DB01                       DB13 DB20 DB21 DB31 DB39                       DC01 DC13 DC18 DC30 DC36                       DC38 EA02 EA07 EA15 EA35                       EB13 EB51 EB52                 4J040 DA001 DA101 JB01 JB09                       LA01

Claims (7)

[Claims] 1. An article comprising a first element and a second element joined to the first element with an adhesive, wherein the adhesive has a [mmmm] pentad concentration of less than 60%. An article comprising a polyolefinic homopolymer having the isotacticity of. 2. Article according to claim 1, wherein the homopolymer has a molecular weight of at least 100,000 g / mol. 3. The article of claim 1, wherein the adhesive is extensible. 4. The article of claim 2, wherein the adhesive is elastically expandable. 5. Polymer adhesive according to any of the preceding claims, characterized in that the homopolymer is polypropylene. 6. Article according to any of the preceding claims, characterized in that the adhesive is arranged as a building element. 7. A hot melt, a spray, a powder melt, an extrusion bead, a liquid,
A method for providing an adhesive coating comprising the step of applying an adhesive coating comprising the group consisting of solvent-based, pressure sensitive and combinations thereof, wherein the polymeric material comprises less than 60% [ mmmm] pentad concentration isotacticity of the polyolefinic homopolymer.