Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J123/00—Adhesives based on homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Adhesives based on derivatives of such polymers
  • C09J123/02—Adhesives based on homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Adhesives based on derivatives of such polymers not modified by chemical after-treatment
  • C09J123/10—Homopolymers or copolymers of propene
  • C09J123/12—Polypropene
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J123/00—Adhesives based on homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Adhesives based on derivatives of such polymers
  • C09J123/02—Adhesives based on homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Adhesives based on derivatives of such polymers not modified by chemical after-treatment
  • C09J123/10—Homopolymers or copolymers of propene
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J9/00—Adhesives characterised by their physical nature or the effects produced, e.g. glue sticks

Definitions

• the present invention relates to adhesives used for example in assembling articles. Specifically, the present invention relates to elastic adhesives.
• Adhesives and in particular adhesives comprising olefinic polymers are well known in the art and enjoy widespread usage throughout the industry. Typical areas of application of such adhesive include hygienic articles and in particular disposable absorbent articles, packaging materials, automotive parts, and the like.
• Adhesives made from commonly used polyolefins such as PP, PE, PS, PIB have a number of useful properties. They are bio-compatible and food compatible, chemically stabile, inert, non toxic materials. However, most of them have poor mechanical properties including insufficient strength/tear resistance, insufficient stretchability/elasticity and the like.
• PU adhesives have also been widely used for example because of their elastic properties.
• PU adhesives however have the disadvantage that they are polymerized from the very toxic monomer isocyanate and hence can not be used for many application due to their inherent toxicity caused by residual monomer content.
• the third approach proposed in the prior art to provide elastic properties to such adhesives, which is more close to the present invention, is to exploit the formation of hetero-phases which reinforce the bulk material by forming a physical net.
• the block-co-polymerization of two or more different monomers has been used leading to polymeric backbones comprising blocks with different Tg. This results in micro-phase separation in the bulk with formation of reinforcing crystalline domains of one co-polymer linked with each other by flexible chains of the second co-polymer.
• conventional adhesives carry a wide variety of inherent disadvantages including but not being limited to insufficient strength/tear resistance, insufficient stretchability/elasticity, not being bio-compatible, not being food compatible, comprising heteroatoms such as chlorine and hence leading to toxic residues when burnt, and the like.
• the present invention provides an article comprising a first element and a second element being joined to said first element by means of an adhesive.
• the article is characterized in that said adhesive comprises said adhesive comprises a polyolefinic homopolymer having an isotacticity of less than 60% of [mmmm] pentad concentration.
• the present invention further provides a method for providing the aforementioned adhesive coating comprising a step of applying an adhesive coating selected from the group of hot melt, spray, powder melt, extruded bead, liquid, solvent based, pressure sensitive, and combinations thereof.
• the present invention provides an article comprising a first element and a second element being joined to said first element by means of an elastic adhesive comprising a polyolefinic homopolymer.
• polyolefinic homopolymer refers to those polyolefins which comprise only one phase of molecules all of which exhibiting a similar stereochemical configuration. For example, blends of atactic and isotactic polymers where the two phases have polymerized simultaneously are excluded when this term is used.
• homopolymer includes copolymers where all molecules exhibit a similar stereochemical configuration.
• the polyolefinic homopolymer of the present invention may comprise linear isotactic polymers having a structure of one or several C 3 to C 20 olefinic monomers, having an isotacticity of less than 60%, preferably less than 50%, more preferably less than 40%, and most preferably less than 30% of [mmmm] pentad concentration, and having an isotacticity of more 8%, preferably more than 10%, more preferably more than 12%, and most preferably more than 15% of [mmmm] pentad concentration.
• the polyolefinic homopolymer is polypropylene.
• the isotacticity of the homopolymers may be reduced compared to the isotactic polypropylenes of the prior art due to a statistic distribution of stereoscopic errors in the polymer chain.
• stereoscopic error refers to a stereoscopic sequence characterized by a [mrrm] pentad.
• the central monomer has a stereo configuration opposed to the other four monomers in this pentad.
• the pentad concentration is at least [p (l-p)] q p (1-p) with q being 0.8, more preferably q being 0.6, yet more preferably q being 0.4, yet more preferably q being 0.2, most preferably q being 0.1.
• the [rmrm] pentad concentration is below 6%, more preferably below 5%, yet more preferably below 4%, yet more preferably below 3%, most preferably below 2.5%.
• the homopolymer of the present invention may include sequences of atactic and isotactic blocks of polymer.
• the mean molecular weight M w of the polymer is above 100000 g/mol, more preferably above 200000 g/mol, yet more preferably above 250000 g/mol, yet more preferably more than 300000 g/mol, most preferably more than 350000 g/mol.
• Higher molecular weights are particularly beneficial where elastic and tear resistance properties of the adhesive material desired.
• the molecular weight is below 200000g/mol, more preferably below 175000g/mol, most preferably below 150000g/mol.
• the glass temperature T g is between -50 and +30 °C.
• the glass temperature is below 10°C, more preferably below 5°C, yet more preferably below 0°C, most preferably below -6°C.
• the melt temperature of the polymer is obtained after heating the sample 150°C and subsequently cooling the polymer to -50°C.
• the polyolefinic polymers exhibit a semi-crystalline structure.
• the structure contains elastic amorphous areas of nano-scale-size reinforced with self arranged crystalline domains of nano-crystals.
• the formation of brittle macro-crystalline material from the polymer is achieved by introducing the defects into the polymeric backbone. Isolated monomer units with opposite stereo configuration have been used as the defects, i.e. single stereo errors.
• Suitable polymers and a process for manufacturing such polymers are described in PCT patent application EP99/02379 incorporated herein by reference.
• a catalyst combination suitable for the preparation of such polymers is described in PCT patent application EP99/02378 incorporated herein by reference.
• the process of PCT patent application EP99/02378 is carried out by temperatures of less than 30°C, more preferably less than 25°C, yet more preferably less than 20°C, most preferably less than 15°C to increase the molecular weight of the resulting polymer.
• the polymerization is preferably carried out in liquid monomer such as in liquid propene.
• the catalyst is preferably used in combination with the boron activators mentioned in PCT patent application EP99/02378.
• the adhesive of the present invention has been found to be able to adhere to polished surfaces such as metal plates, PTFE coated surfaces, polymeric surfaces and the like.
• the adhesive of the present invention is also suitable for adhering to mammalian tissue such as epidermal tissue.
• the adhesion force between the two elements of the article of the present invention is adjusted to be at least 5 Newton per centimeter, more preferably at least lON/cm, yet more preferably 20N/cm, most preferably 40N/cm.
• the adhesive properties such as molecular weight can be changed accordingly.
• the same peel force requirement apply when surfaces are attached to each other. The peel forces are measured with respect to the specific surfaces they are used on.
• the adhesive of the present invention has further been found to only release relative small amounts of odor even in the melt state.
• the adhesive of the present invention has been found to exhibit increased temperature stability compared to prior art adhesives. This is partly due to the fact that for the adhesives of the present invention a homopolymer is used and is partly due to the high molecular weight of the homopolymer.
• the adhesive material of the present invention has a melting point of at least 100°C, more preferably of at least 110°C, more preferably of at least 120°C, most preferably of at least 130°C. The melt temperature of the polymer is obtained after heating the sample 150°C and subsequently cooling the polymer to -50°C. If desired, higher melting point may be achieved my blending the homopolymer for example with conventional isotactic polymer such as polypropylene.
• melting point of around 50°C can be achieved. Such melting point can be used for deactivating the adhesive where this is desired. Heating the adhesive to its melting point will cause the adhesive to flow and hence in can be peeled off at very low peel forces.
• the adhesive of the present invention has been found to be stretchable as well as elastic.
• the stretchability of the adhesive versus its elastic behavior can be adjusted by means of the tacticity of the homopolymer of the present invention.
• the adhesive material of the present invention has been found to be stretchable without tearing to at least 500% of its original length, more preferably 1000% of its original length, yet more preferably to at least 1500% of its original length, most preferably to at least 2000% of its original length.
• the adhesive material of the present invention preferably recovers within 10 minutes after being stretched and held for 1 minute to 500% of its original length back to less than 300% its original length, preferably less than 200% its original length, most preferably less than 150% of its original length.
• the adhesive of the present invention has been found to exhibit a low compressive set.
• the adhesive of the present invention recovers within 10 minutes after a compression to 50% of its original thickness for 1 minute to at least 60% of its original thickness, more preferably at least 70% of its original thickness, yet more preferably to at least 80% of its original thickness, yet more preferably to at least 90% of its original thickness, most preferably to at least 95% of its original thickness.
• the compressibility of the adhesive of the present invention can be adjusted by increasing the tacticity of the homopolymer or by blending the low tacticity homopolymer with conventional isotactic polymer such as polypropylene.
• the rheological properties of the adhesive of the present invention i.e. the storage or elastic modulus G' and the viscosity modulus G" are indicative of its creep and its peel/quick stick behavior respectively during use.
• the G' and G" values at low frequencies are believed to relate to the behavior of the adhesive at application and at removal respectively. It is well known in the art, to measure G' and G" over a broad range of frequencies, for example a Rheometric Scientific RS-5 rheometer could be used.
• the adhesive of the present invention has a viscosity modulus G"(lrad/s) of less than 30000 Pa, more preferably less than 25000 Pa, yet more preferably less than 20000 Pa, most preferably less than 15000 Pa.
• G"(lrad/s) are indicative of the adhesive not flowing away when the adhesive is applied to the surface.
• the adhesive of the present invention has a viscosity modulus G"(lrad/s) of at least 500 Pa, more preferably at least 1000 Pa, yet more preferably at least 1500 Pa, most preferably at least 2000 Pa.
• G"(lrad/s) are indicative of the adhesive being able to conform to the topology of the surface it is applied to.
• the adhesive of the present invention has a viscosity modulus G"(100rad/s) of less than 30000 Pa, more preferably less than 20000 Pa, yet more preferably less than 15000 Pa, most preferably less than 10000 Pa.
• G"(100rad/s) are indicative of the adhesive not flowing away upon removal from the surface.
• the adhesive of the present invention has a viscosity modulus G"(100rad/s) of at least 1000 Pa, more preferably at least 2000 Pa, yet more preferably at least 3000 Pa, most preferably at least 4000 Pa.
• G"(100rad/s) are indicative of the adhesive not breaking upon removal from the surface.
• the adhesive of the present invention has a viscosity modulus G'(lrad/s) of less than 30000 Pa, more preferably less than 25000 Pa, yet more preferably less than 20000 Pa, most preferably less than 15000 Pa.
• the adhesive of the present invention has a viscosity modulus G'(lrad/s) of at least 500 Pa, more preferably at least 1000 Pa, yet more preferably at least 1500 Pa, most preferably at least 2000 Pa.
• G'(lrad/s) are indicative of the adhesive maintaining its elastic properties when the adhesive is applied to the surface.
• the adhesive of the present invention has a viscosity modulus G'(100rad/s) of less than 30000 Pa, more preferably less than 25000 Pa, yet more preferably less than 20000 Pa, most preferably less than 15000 Pa.
• the adhesive of the present invention has a viscosity modulus G'(100rad/s) of at least 2000 Pa, more preferably at least 3000 Pa, yet more preferably at least 4000 Pa, most preferably at least 5000 Pa.
• G'(100rad/s) are indicative of the adhesive maintaining its elastic properties upon removal from the surface.
• the ratio of G'(l rad/s) / G"(l rad/s) is in the range of 1 to 30. This is believed to be indicative of the flow behavior of the adhesive of the present invention during application of the adhesive to the surface of the substrate.
• the adhesive according to the present invention may also be used as a construction element in an article.
• Such articles include but are not limited to toys, furniture, clothing, shoes, sport equipment, complex constructions such as buildings, cars, household appliances, and the like.
• the adhesives of the present invention are suitable for joining non-sealable polyolefinic surfaces, for joining and adhering to wood surfaces, for joining and adhering to Plexiglas surfaces and the like.
• the adhesives are suitable for applications where the adhesive needs to be stretchable, i.e. where the bonded surfaces of the first element and the second element should be allowed to make small movements relative to each other.
• the adhesive of the present invention may be used as a binder resin for nonwoven web materials.
• the adhesive of the present invention will allow for further processing of such bonded nonwoven web materials such as for example mechanical activation such as by ring rolling.
• the adhesives of the present invention may for example be activated by electromagnetic radiation such as infrared, UV or visible radiation, by ultrasonic wave and the like.
• Additives such as those known in the art may be added to the adhesive of the present invention.
• the addition of talc is suitable for modifying the adhesive properties.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Adhesives Or Adhesive Processes (AREA)
• Application Of Or Painting With Fluid Materials (AREA)

Priority Applications (7)

Applications Claiming Priority (2)

Publications (1)

Family

ID=8239167

Family Applications (1)

Country Status (9)

Cited By (2)

Families Citing this family (5)

Citations (4)

• 2000
  • 2000-10-02 WO PCT/US2000/027137 patent/WO2001027213A1/en not_active Application Discontinuation
  • 2000-10-02 EP EP00968576A patent/EP1238035A1/en not_active Withdrawn
  • 2000-10-02 CA CA002386904A patent/CA2386904A1/en not_active Abandoned
  • 2000-10-02 JP JP2001530419A patent/JP2003511541A/ja not_active Withdrawn
  • 2000-10-02 CN CNB008140448A patent/CN1179013C/zh not_active Expired - Fee Related
  • 2000-10-02 MX MXPA02003509A patent/MXPA02003509A/es not_active Application Discontinuation
  • 2000-10-02 AU AU78469/00A patent/AU776090B2/en not_active Ceased
  • 2000-10-02 KR KR10-2002-7004491A patent/KR100497591B1/ko not_active IP Right Cessation
  • 2000-10-02 BR BR0014609-9A patent/BR0014609A/pt not_active IP Right Cessation

Patent Citations (4)

Non-Patent Citations (1)

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