Friction-Activated Adhesive Formulations for Bonding

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional friction-activated adhesive sticks have poor writability, minimal tack, short open time, and poor adhesion properties, requiring high pressures or temperatures for bonding, making them user-unfriendly and inefficient.

Innovation Solution

Development of novel friction-activated adhesive formulations using semi-crystalline polymers with specific monomers, tackifiers, and additives, which are molded into glue crayon shapes for easy application, providing improved tackiness, adhesion, and stability without the need for volatile solvents or special packaging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional friction-activated adhesive sticks are used, then the adhesive can be applied in solid form, but the writability is poor and high pressure is required for bonding

Engineering Contradiction:
ImprovewritabilityVSAvoidpressure required for bonding
Core Design Contradiction:
Ease of operationVSForce

Solution Approach 1:

The patent modifies the physical and chemical parameters of the adhesive composition by incorporating specific semi-crystalline polymers with controlled melting points, tackifiers, and plasticizers. This changes the adhesive's softening temperature and tack characteristics, allowing it to become sufficiently soft and tacky at room temperature with minimal rubbing pressure, thereby improving writability while reducing the force required for bonding.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite adhesive system combining semi-crystalline polymers (providing structural framework and melting behavior), tackifiers (providing adhesion), and plasticizers (providing flexibility and softness). This composite formulation achieves optimal balance between writability and bonding strength, allowing the adhesive to be easily applied with minimal pressure while maintaining strong bonding capability.

Inventive Principle:
Principle #40Composite materials

2Duration of action of moving object

If conventional friction-activated adhesive sticks are used, then the adhesive can be stored as solid, but the open time is minimal

Engineering Contradiction:
Improveopen timeVSAvoidadhesion properties
Core Design Contradiction:
Duration of action of moving objectVSReliability

Solution Approach 1:

The patent adjusts the melting point and tack parameters of the adhesive by selecting semi-crystalline polymers with specific melting ranges and incorporating tackifiers in optimized amounts. This creates an adhesive that remains solid during storage but softens to the appropriate tack level upon frictional heating, extending the open time while maintaining reliable adhesion properties throughout the extended bonding window.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If conventional adhesive formulations are used, then bonding can be achieved, but volatile solvents require special packaging to prevent drying out

Engineering Contradiction:
Improvebonding capabilityVSAvoidpackaging requirements
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts and eliminates volatile solvent components from the adhesive formulation, replacing them with non-volatile semi-crystalline polymers, tackifiers, and plasticizers. This extraction of harmful volatile components allows the adhesive to be stored in simple containers without special sealing requirements, as the composition does not dry out or evaporate, thereby reducing packaging complexity while maintaining bonding capability.

Inventive Principle:
Principle #2Taking out (Extraction)

4Reliability

If conventional friction-activated adhesive sticks are used, then the adhesive can be applied, but the adhesion properties are poor

Engineering Contradiction:
Improveadhesion propertiesVSAvoidapplication ease
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The invention formulates a composite adhesive system where semi-crystalline polymers provide the base structure, tackifiers enhance adhesion properties, and plasticizers improve applicability. This composite approach ensures that the adhesive has sufficient tack and adhesion strength while remaining easy to apply with minimal rubbing, resolving the contradiction between adhesion performance and application ease.

Inventive Principle:
Principle #40Composite materials

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The adhesive formulations offer improved writability, instant adhesion, long-term stability, and reduced packaging needs, allowing for secure bonding with minimal pressure and no drying out, making them suitable for various applications without the drawbacks of traditional adhesives.

Implementation Method 1

friction-activated adhesive formulations

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

solid thermoplastic friction-activated adhesive composition

Methodology Applied
Scientific EffectMelting: Melting

Data Source

PatentUS11267997B2Friction-activated adhesive formulations and application devices
Publication Date: 2022.03.08 3M INNOVATIVE PROPERTIES CO

AI summary

A solid thermoplastic semi-crystalline friction-activated adhesive composition comprising the mixture of:(a) from about 50 to about 100 parts by weight of a semi-crystalline adhesive polymer that comprises:(1) crystalline monomer having an alkyl carbon length of at least 16 carbon atoms;(2) non-crystalline monomer having a homopolymer Tg below about 80° C.;(3) waxy, soft monomer having an average pendant alkyl carbon length of at least 14 carbon atoms;(4) monomer having acid or base functionality;(5) functional or non-functional macromere having a Tm from about 40 to about 120° C.;(b) 0 to about 50 parts by weight of tackifier;(c) 0 to about 50 parts by weight of crystalline additive;(d) 0 to about 50 parts by weight of filler;(e) 0 to about 30 parts by weight of oil; and(f) 0 to about 50 parts by weight of one surfactant.Also glue crayons and other application devices comprising such adhesive compositions.