Hot melt adhesive for elastic banding

• US 4,259,220 A
• Filed: 05/07/1979
• Issued: 03/31/1981
• Est. Priority Date: 12/06/1978
• Status: Expired due to Term

• Current Assignee: H.B. Fuller Licensing & Financing, Inc.
• Original Assignee: HB Fuller Company
• Inventors: Bunnelle, William L., Lindmark, Richard C. Jr.
• Primary Examiner(s): Pianalto, Bernard D.
• Application Number:
  US06/036,858
• Time in Patent Office: 694 Days
• Field of Search: 427/207 A, 427/207 B, 525/901, 525/93, 525/97, 525/98, 525/99, 260/27 BB
• US Class Current: 525/98
• CPC Class Codes: A61F 13/15593 having elastic ribbons fixed thereto; Devices for applying the ribbons
• CPC Class Codes: B32B 2307/718 Weight, e.g. weight per square meter
• CPC Class Codes: B32B 2307/72 Density
• CPC Class Codes: B32B 2309/02 Temperature
• CPC Class Codes: B32B 2555/02 Diapers or napkins
• CPC Class Codes: B32B 37/1207 Heat-activated adhesive B32B37/04 takes precedence
• CPC Class Codes: B32B 37/144 using layers with different mechanical or chemical conditions or properties, e.g. layers with different thermal shrinkage, layers under tension during bonding constructional features for tensioning B32B38/1825

Abstract

A viscoelastic hot melt pressure-sensitive adhesive consisting essentially of:

(a) about 35 to about 55% by weight of a rubbery block copolymer which comprises a rubbery polyisoprene midblock portion and a plurality of end blocks comprising a crystalline poly(vinylarene);

(b) about 25 to 45% by weight of a terpene tackifying resin generally compatible with and generally associated with said midblock portion;

(c) about 10 to about 30% by weight of an aromatic, essentially hydrocarbon resin having a glass transition temperature and a softening point above about 115° C., said essentially hydrocarbon resin being generally compatible with said end blocks of said rubbery block copolymer;

the proportions of said components (a), (b), and (c) being selected to provide the following pressure-sensitive adhesive and rheological properties:

(i) a tensile strength at 500% elongation, determined at 20°-25° C., of at least 50 pounds per square inch;

(ii) a 180° peel resistance, according to PSTC-1, determined at 20°-25° C. 24 hours after formation of the pressure-sensitive adhesive bond, of at least about 1500 grams per 25.4 mm-width;

(iii) a dead load deformation, tested at room temperature, 37.8° C., 43.3° C., and 48.9° C. for 3 hours under 1500 g/cm², of less than 100%, where dead load deformation=the increased length minus the original length divided by the original length of a sample at least 25 mm in length;

(iv) the following loss modulus, storage modulus, and loss tangent values at 0.01 and 0.25 Hz throughout the temperature range of 25°-50° C.:

______________________________________                                    

0.01 Hz 0.25 Hz ______________________________________ loss modulus 5-100 0-100 10⁴ dynes/cm² storage modulus, 65-225 75-200 10⁴ dynes/cm² loss tangent 0.03-1.0 0.08-1.0 ______________________________________

wherein the said values remain generally within the following limits, throughout said temperature range, at 0.25 Hz:______________________________________loss modulus ±70 × 10⁴ dynes/cm²storage Modulus ±40 × 10⁴ dynes/cm²loss tangent ±0.6.______________________________________ .

Claims

1. A viscoelastic hot melt pressure-sensitive adhesive consisting essentially of:

(a) about 35 to about 55% by weight of a rubbery block copolymer which comprises a rubbery polyisoprene midblock portion and a plurality of end blocks comprising a crystalline poly(vinylarene);

(b) about 25 to 45% by weight of a terpene tackifying resin generally compatible with and generally associated with said midblock portion;

(c) about 10 to about 30% by weight of an aromatic, essentially hydrocarbon resin having a glass transition temperature and a softening point above about 115°

C., said essentially hydrocarbon resin being generally compatible with said end blocks of said rubbery block copolymer;

the proportions of said components (a), (b), and (c) being selected to provide the following pressure-sensitive adhesive and rheological properties;

(i) a tensile strength at 500% elongation, determined at 20°

-25°

C., of at least 50 pounds per square inch;

(ii) a 180°

peel resistance, according to PSTC-1, determined at 20°

-25°

C. 24 hours after formation of the pressure-sensitive adhesive bond, of at least about 1500 grams per 25.4 mm-width;

(iii) a dead load deformation, tested at room temperature, 37.8°

C., 43.3°

C., and 48.9°

C. for 3 hours under 1500 g/cm², of less than 100%, where dead load deformation=the increased length minus the original length divided by the original length of a sample at least 25 mm in length;

(iv) the following loss modulus, storage modulus, and loss tangent values at 0.01 and 0.25 Hz throughout the temperature range of 25°

-50°

C.;

space="preserve" listing-type="tabular">______________________________________ 0.01 Hz 0.25 Hz ______________________________________ loss modulus 5-100 0-100 10.sup.4 dynes/cm.sup.2 storage modulus, 65-225 75-200 10.sup.4 dynes/cm.sup.2 loss tangent 0.03-1.0 0.08-1.0 ______________________________________

wherein the said values remain generally within the following limits, throughout said temperature range, at 0.25 Hz;

space="preserve" listing-type="tabular">______________________________________ loss modulus ±

70 ×

10.sup.4 dynes/cm.sup.2 storage Modulus ±

40 ×

10.sup.4 dynes/cm.sup.2 loss tangent ±

0.6. ______________________________________

2. A viscoelastic hot melt pressure-sensitive adhesive according to claim 1, wherein said adhesive consists essentially of:

up to 85 parts by weight, per 100 parts by weight of said block copolymer, of said terpene tackifying resin, said tackifying resin having been synthetically derived from a mixed olefin feedstock;

up to 65 parts by weight, per 100 parts by weight of said block copolymer, of said essentially hydrocarbon resin, said essentially hydrocarbon resin having a softening point of at least about 140°

C.;

0-5% by weight of substantially inert extenders, fillers, pigments, and antioxidants;

the foregoing proportions being selected to provide the following loss modulus, storage modulus, loss tangent, storage compliance, and loss compliance values, throughout the temperature range of 25°

-50°

C., at 0.01 Hz;

space="preserve" listing-type="tabular">______________________________________ loss modulus, 10.sup.4 dynes/cm.sup.2 5-25 storage modulus, 10.sup.4 dynes/cm.sup.2 75-200 loss tangent 0.05-0.3 storage compliance, 10.sup.-8 cm.sup.2 /dyne 40-100 loss compliance, 10.sup.-8 cm.sup.2 /dyne 2-20 ______________________________________

and the following storage compliance and loss compliance values, throughout said temperature range at 0.25 Hz;

space="preserve" listing-type="tabular">______________________________________ storage compliance, 10.sup.-8 cm.sup.2 /dyne 40-100 loss compliance, 10.sup.-8 cm.sup.2 /dyne 5-40. ______________________________________

3. A viscoelastic hot melt pressure sensitive adhesive according to claim 2, wherein said aromatic, essentially hydrocarbon resin is a coumarone-indene resin.