Joining material for laser welding and laser welding method using the same

Patent metadata

Field	Value
Publication number	US-11535734-B2
Application number	US-201816769051-A
Country	US
Kind code	B2
Filing date	Dec 7, 2018
Priority date	Dec 7, 2017
Publication date	Dec 27, 2022
Grant date	Dec 27, 2022

Abstract

A joining material for laser welding, a laser welding method using the same, and a laser joined body using the laser welding method. The joining material includes a polymer matrix and a needle-shaped inorganic filler. The polymer matrix includes a polypropylene resin having a melt index of 80 g/10 min or more to 95 g/10 min or less as measured at a temperature of 230° C. and a load of 2.16 kg, and the needle-shaped inorganic filler has an aspect ratio of 10:1 to 20:1.

First claim

The invention claimed is:

1. A joining material for laser welding, the joining material comprising:
a polymer matrix comprising a polypropylene resin having a melt index of 80 g/10 min or more to 95 g/10 min or less as measured at a temperature of 230° C. and a load of 2.16 kg; and
a needle-shaped inorganic filler having an aspect ratio of 10:1 to 20:1,
wherein the joining material has a light transmittance of 20% or more and 30% or less at a wavelength of 980 nm.

2. The joining material of claim 1 , wherein the polymer matrix further comprises a thermoplastic elastomer.

3. The joining material of claim 2 , wherein the thermoplastic elastomer comprises a block copolymer of ethylene and an α-olefin having 4 to 30 carbon atoms.

4. The joining material of claim 3 , wherein a molar ratio of the ethylene to the α-olefin is 6:4 to 7:3.

5. The laser joining material of claim 3 , wherein the α-olefin having 4 to 30 carbon atoms comprises at least one α-olefin selected from the group consisting of 1-butene, 1-pentene, 4-methyl-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, 1-hexadecene, and 1-eicosene.

6. The joining material of claim 2 , wherein the thermoplastic elastomer has a melt index of 0.5 g/10 min or more to 10 g/10 min or less as measured at a temperature of 190° C. and a load of 2.16 kg.

7. The joining material of claim 2 , wherein the thermoplastic elastomer is present in an amount of 5 parts or more by weight to 30 parts or less by weight based on 100 parts by weight of the joining material.

8. The joining material of claim 1 , wherein the polypropylene resin comprises at least one selected from the group consisting of a propylene homopolymer, an ethylene-propylene copolymer, a copolymer of propylene and an olefin-based monomer having 4 to 10 carbon atoms, and a block copolymer of polypropylene and an ethylene-propylene rubber.

9. The joining material of claim 8 , wherein, when the polypropylene resin is an ethylene-propylene copolymer, a content of an ethylene repeating unit of the ethylene-propylene copolymer is 3 wt % or more to 10 wt % or less.

10. The joining material of claim 1 , wherein the needle-shaped inorganic filler is present in an amount of 5 parts or more by weight to 30 parts or less by weight based on 100 parts by weight of the joining material.

11. The joining material of claim 1 , wherein the joining material has a thickness of 0.5 mm or more to 5 mm or less.

12. The laser joining material of claim 1 , wherein the needle-shaped inorganic filler is selected from the group consisting of magnesium oxysulfate-based particles, magnesium silicate hydrate-based particles and calcium silicate-based particles.

13. A laser welding method comprising:
laminating the joining material according to claim 1 and at least a part of a material to be joined; and
irradiating a region where the joining material and the material to be joined are laminated with a laser to form a welding region,
wherein the laser passes through the joining material toward a surface of the material to be joined.

14. The method of claim 13 , wherein a total line energy of the laser is 1.5 J/mm or more to 3 J/mm or less, wherein the total line energy is defined by Equation 1:
E tot =P/v ×the number of repetitions, and  1

wherein in Equation 1, E tot is the total line energy (J/mm), P is a laser power (W), and v is a laser irradiation rate (mm/s).

15. A laser joined body manufactured by using the laser welding method according to claim 13 .

Assignees

• Lg Chemical Ltd
• Lg Hausys Ltd

Inventors

• Jung Jin Mi
• Park Chun Ho
• Yoo Jae Jung
• Jeong Yu Jin
• Lee Seung Yong
• Lee Soo Min
• Son Bu Won
• Shin Bu Gon

Classifications

• B29C65/1635

  at least passing through one of the parts to be joined, i.e. laser transmission welding · CPC title

• B29C65/8215

  Tensile tests · CPC title

• B29C66/71

  characterised by the composition of the plastics material of the parts to be joined (welding bar compositions B29C65/125) · CPC title

• C08F210/06

  Propene · CPC title

• B29C65/1674

  making use of laser diodes (B29C65/167 takes precedence) · CPC title