CN116221682A - String lamp and manufacturing method thereof - Google Patents

Abstract

The invention relates to a decorative string lamp, which comprises a plurality of lamp beads with at least two conductive pins, an electric wire for connecting the lamp beads, a separation block arranged between the at least two conductive pins of the lamp beads, and a sheath wrapping the joint of the at least two conductive pins and the electric wire. The sheath is a flexible sheath, and the raw materials of the sheath comprise the following components: 40-74 parts of ethylene-vinyl acetate copolymer or polyethylene resin or a mixture of the two, 5-20 parts of filler, 0.1-5 parts of ultraviolet initiator, 0.1-5 parts of cross-linking agent, 0.1-1 part of light stabilizer, 20-50 parts of flame retardant and 0.1-5 parts of lubricant. According to the sheath of the string lamp, the proportion of the ethylene-vinyl acetate copolymer or the polyethylene resin, the cross-linking agent, the light stabilizer, the flame retardant and the lubricant is reasonably configured, so that the voltage resistance of the prepared sheath reaches 1500V, and the flame retardant grade reaches above SC-1.

Description

String lamp and manufacturing method thereof

Technical Field

The invention relates to a decorative string lamp, in particular to a decorative string lamp and a manufacturing method thereof.

Background

The decorative string lamp is a strip-shaped decorative lamp composed of a plurality of lamp beads connected by wires, and is widely used for decoration of various holiday and shops and stores. The string light is flexible and bendable, so that the string light is very convenient to use. Meanwhile, the existing string lamp mostly adopts LED lamp beads, and generates heat greatly when in use, so that the requirements on connection between wires and pins of the lamp beads and protection devices are relatively high. The connection and protection device needs to be resistant to high pressure and flame. Existing connection and protection devices have both rigid and flexible sheaths. Wherein the flexible sheath cannot pass a 1500V voltage breakdown experiment, and the flame retardant grade is also insufficient.

Disclosure of Invention

The invention aims to provide a string lamp with a sheath with a withstand voltage reaching 1500V and a flame retardant grade reaching SC-1 and a manufacturing method thereof.

A string lamp comprises a plurality of lamp beads with at least two conductive pins, wires for connecting the lamp beads, a separation block arranged between the at least two conductive pins of the lamp beads, and a sheath wrapping the joint of the at least two conductive pins and the wires. The sheath is a flexible sheath, and the raw materials of the sheath comprise the following components:

40-74 parts of ethylene-vinyl acetate copolymer or polyethylene resin or a mixture of the two;

5-20 parts of filler;

0.1-5 parts of ultraviolet initiator;

0.1-5 parts of cross-linking agent;

0.1-1 part of light stabilizer;

20-50 parts of flame retardant;

0.1-5 parts of lubricant.

By adopting the technical scheme, the sheath can pass a 1500V voltage breakdown experiment, and the flame retardant grade reaches above SC-1. The sheath is not easy to crack after long-time use, and the service life is long.

The filler is used for improving the strength of the product and reducing the cost, and calcium carbonate, talcum powder and the like can be adopted.

The ultraviolet initiator determines the curing rate and the curing degree of the sheath, and has very important influence on the performance of the sheath. The ultraviolet initiator can be an organic carbonyl compound.

The crosslinking agent may be an allyl crosslinking agent.

The light stabilizer may be a hindered amine or piperidine compound.

The flame retardant can be one or more halogen-free environment-friendly flame retardants with nano aluminum hydroxide, nano magnesium hydroxide and bromine-antimony compounded flame retardant system and phosphorus nitrogen as flame retardant elements.

The lubricant may be one of stearic acid, a mixture of pentaerythritol mono/distearate, oxidized polyethylene wax.

As one embodiment, the raw materials of the sheath further comprise 0.1-5 parts of coupling agent. The coupling agent employs a silane coupling agent having a functional group such as at least one of vinyl, acryl, amino, chlorine, and phenoxy.

As one embodiment, the raw materials of the sheath can further comprise 0.1-5 parts of antioxidant.

The antioxidant can be hindered phenol antioxidant or phosphite antioxidant or both.

As one embodiment, the uv initiator is a cationic or free radical uv initiator.

A method of manufacturing a string light, comprising the steps of:

s1, providing an electric wire with a bare cell section, a lamp bead with at least two conductive pins, an isolation block and a sheath subjected to secondary expansion;

s2, electrically and physically connecting the conductive pins of the lamp beads with the corresponding exposed core sections of the wires;

s3, fixing the isolation block between at least two conductive pins of each lamp bead to prevent circuit breaking;

s4, cutting a sheath with preset length and sleeving the sheath at the joint of the lamp bead and the wire; and

s5, heating the sheath to shrink and tightly wrap the joint of the lamp bead and the wire.

Wherein the raw materials of the sheath are the same as the raw materials of the sheath.

As one embodiment, the method of providing the secondarily expanded sheath comprises:

s11, mixing the raw materials of the sheath and stirring uniformly to obtain a mixture; extruding the mixture into granules;

s12, extruding the particles into a hollow tubular object;

s13, performing cross-linking and curing on the hollow tubular object by utilizing ultraviolet light to form a primary sheath;

and S14, heating the primary sheath, and applying internal pressure to the primary sheath to expand the primary sheath in the radial direction to form the sheath subjected to secondary expansion.

As one embodiment, the heating temperature in step S14 and step S5 is 80-120 degrees.

According to the sheath of the string lamp, the proportion of the ethylene-vinyl acetate copolymer or the polyethylene resin to the filler, the cross-linking agent, the light stabilizer, the flame retardant and the lubricant is reasonably configured, so that the voltage resistance of the prepared sheath reaches 1500V, the flame retardant grade reaches SC-1 or above, and the UL certification standard in the United states is met.

Drawings

Fig. 1 is a schematic diagram of a string light according to an embodiment of the invention.

Fig. 2 is a cross-sectional view of the lamp bulb and a portion of the wire of the string light of fig. 1.

Description of the embodiments

The present invention will now be described in detail with reference to the drawings and examples, which are only preferred embodiments of the present invention and are not limiting thereof.

Referring to fig. 1, an LED string lamp mainly includes a power plug 10, an electric wire 20 with two ends electrically connected to the power plug 10, and a plurality of light emitting devices 30 electrically connected to the electric wire 20. Wherein the light emitting device 30 mainly comprises a lamp bead 31, a spacer 33 and a sheath 34.

The lamp bead 31 may include a chip and an LED lamp mounted on the chip, and two conductive pins 32 electrically connected to the chip and extending from one end of the lamp bead 32 are connected to the wires 20 and physically. The conductive pins 32 of the lamp beads 31 may be directly welded to the core wires of the electric wires 20, or may be connected together by a conductive fixture. The isolating block 33 is made of a non-conductive plastic material, and is disposed between the conductive pins 32 of the lamp bead 31, so that the two conductive pins 32 are electrically isolated from each other, and meanwhile, the connection portions of the two wires and the two conductive pins 32, and the exposed core wires of the two wires are electrically isolated from each other, so that the lamp bead 31 can normally light up without occurrence of a short circuit phenomenon when the wires 20 are electrified.

The sheath 34 is a heat-shrinkable flexible sheath, is non-conductive, is sleeved at the joint of the lamp bead 31 and the electric wire 20, tightly wraps all of the conductive pin 32 and the isolation block 33 and plays roles of insulating, fixing and preventing abrasion of the joint of the conductive pin 32 and the electric wire 20. It will be appreciated that the wire 20 is stripped from the conductive pin 32 and the sheath 34 should encapsulate all of the stripped exposed core wire and even a portion of the stripped wire to ensure the insulation of the circuit. Because the heat-shrinkable flexible sheath is adopted, the sheath 34 is tightly wrapped on the outer side, and the situation that the lamp beads fall off or the wires are torn off in the process of using the string lamp can be effectively prevented.

In the various examples and comparative examples, the raw material components of the sheath were calculated in terms of weight parts as shown in table 1.

The sheath is a sheath subjected to secondary expansion, and the manufacturing method thereof comprises the following steps S11 to S14.

S11, mixing the raw materials of the sheath, stirring uniformly to obtain a mixture, and processing the mixture into particles through extrusion.

S12, extruding the particles obtained in the step S11 into a hollow tubular object, wherein the wall thickness of the tubular object is between 0.2 and 0.4 mm.

And S13, performing cross-linking and curing on the hollow tubular object obtained in the step S12 by utilizing ultraviolet light to form a primary sheath.

S14, heating the primary sheath obtained in the step S13 to a temperature of about 100 ℃, and applying internal pressure to the primary sheath to expand the primary sheath in the radial direction to form a sheath subjected to secondary expansion.

The manufacturing method of the string light comprises steps S1 to S5.

S1, providing an electric wire with a bare core line segment, a lamp bead with two conductive pins, an isolation block and a sheath subjected to secondary expansion.

S2, electrically and physically connecting the conductive pins of the lamp beads with corresponding exposed core line segments of the electric wires.

S3, inserting the isolation block between the two conductive pins of each lamp bead to prevent circuit breaking.

S4, cutting a sheath with preset length and sleeving the sheath at the joint of the lamp bead and the electric wire.

S5, heating the sheath to shrink and tightly wrap the joint of the lamp bead and the wire. The heating temperature is about 110 ℃.

TABLE 1 jacket formulation table

Composition of the components	Example 1	Example 2	Example 3	Example 4	Comparative example 1	Comparative example 2
							Ethylene-vinyl acetate copolymer	63	50	40	40	40	36
Polyethylene resin	0	7	10	5	37	0
							Filler (B)	10	10	5	5	5	5
Ultraviolet initiator	3	3	3	3	3	3
							Crosslinking agent	0.5	1	1	1	2	2
Light stabilizers	1	0.5	0.5	0.5	0.5	2
							Flame retardant	20	26	38	43	10	51
Lubricant	1	1	1	1	1	0.3
							Coupling agent	1	1	1	1	1	0.3
Antioxidant	0.5	0.5	0.5	0.5	0.5	0.4

TABLE 2 sheath Voltage breakdown and flame retardance test Meter

	Breakdown voltage (Tv)	Flame retardant rating
			Example 1	3491V	Reach SC-1 grade
Example 2	2980V	Reach SC-1 grade
			Example 3	2573V	Reach SC-1 grade
Example 4	1723V	Reach SC-1 grade
			Comparative example 1	4220V	Can not reach the SC-1 grade
Comparative example 2	1230V	Can not reach the SC-1 grade

Therefore, the voltage resistance of the jacket of the formula of the invention reaches 1500V, the flame retardant rating reaches SC-1 or above, and the UL certification standard in the United states is satisfied.

While the invention has been described in conjunction with the specific embodiments above, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, all such alternatives, modifications, and variations are included within the spirit and scope of the following claims.

Claims (10)

1. A string light comprises a plurality of lamp beads with at least two conductive pins, electric wires for connecting the lamp beads, a separation block arranged between the at least two conductive pins of the lamp beads, and a sheath wrapping the connection part of the at least two conductive pins and the electric wires; the sheath is characterized by being a flexible sheath, and the raw materials of the sheath comprise the following components:

40-74 parts of ethylene-vinyl acetate copolymer or polyethylene resin or a mixture of the two;

5-20 parts of filler;

0.1-5 parts of ultraviolet initiator;

0.1-5 parts of cross-linking agent;

0.1-1 part of light stabilizer;

20-50 parts of flame retardant;

0.1-5 parts of lubricant.

2. The string light of claim 1, wherein the raw material of the sheath further comprises 0.1-5 parts of a coupling agent.

3. The string light of claim 1, wherein the raw material of the sheath further comprises 0.1-5 parts of an antioxidant.

4. The cluster of claim 1 wherein the uv initiator is a cationic uv initiator.

5. A method of manufacturing a string light, comprising the steps of:

s1, providing an electric wire with a bare core line segment, a lamp bead with at least two conductive pins, an isolation block and a sheath subjected to secondary expansion;

s2, electrically and physically connecting the conductive pins of the lamp beads with corresponding exposed core line segments of the electric wires;

s3, fixing the isolation block between at least two conductive pins of each lamp bead to prevent circuit breaking;

s4, cutting a sheath with preset length and sleeving the sheath at the joint of the lamp bead and the wire;

s5, heating the sheath to shrink and tightly wrap the joint of the lamp bead and the wire;

wherein the raw materials of the sheath comprise the following components:

40-74 parts of ethylene-vinyl acetate copolymer or polyethylene resin or a mixture of the two;

5-20 parts of filler

0.1-5 parts of ultraviolet initiator;

0.1-5 parts of cross-linking agent;

0.1-1 part of light stabilizer;

20-50 parts of flame retardant;

0.1-5 parts of lubricant.

6. The method of claim 5, wherein the starting material for the sheath further comprises 0.1-5 parts of a coupling agent.

7. The method of claim 1, wherein the raw material of the sheath further comprises 0.1-5 parts of an antioxidant.

8. The method of claim 1, wherein the ultraviolet initiator is a cationic ultraviolet initiator.

9. The method of claim 5, wherein the method of providing the secondarily expanded sheath comprises:

s11, mixing the raw materials of the sheath, uniformly stirring to obtain a mixture, and processing the mixture into particles by using an extruder;

s12, extruding the particles into a hollow tubular object;

s13, performing cross-linking and curing on the hollow tubular object by utilizing ultraviolet light to form a primary sheath;

and S14, heating the primary sheath, and applying internal pressure to the primary sheath to expand the primary sheath in the radial direction to form the sheath subjected to secondary expansion.

10. The method according to claim 10, wherein the heating temperature in step S14 and step S5 is 80-120 degrees.

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