Pressure-responsive particles, cartridge, and apparatus for manufacturing printed matter

1. Pressure-responsive particles comprising:

pressure-responsive base particles; and

silica particles,

wherein the pressure-responsive base particles contain a styrene-based resin that contains styrene and other vinyl monomers as polymerization components and a (meth)acrylic acid ester-based resin that contains at least two (meth)acrylic acid esters as the polymerization components and in which a ratio of a mass of the (meth)acrylic acid esters to a total mass of polymerization components is 90% by mass or more,

the pressure-responsive particles have at least two glass transition temperatures,

a difference between a lowest glass transition temperature and a highest glass transition temperature is 30° C. or higher, and

a ratio of a surface coating rate Cs2 by the silica particles after application of the following first stress to a surface coating rate Cs1 by the silica particles before application of stress satisfies a relationship of 0.4≤ Cs2/Cs1≤0.8,

first stress: 10 g of the pressure-responsive particles and 90 g of resin-coated ferrite particles are put in a V-shaped mixer with a rotary container having a volume of 0.5 L and rotated at a rotation speed of 40 rpm for 20 minutes at a temperature of 20° C. and a relative humidity of 50%,

wherein the at least two kinds of (meth)acrylic acid esters are selected from the group consisting of a 2-ethylhexyl acrylate, a hexyl acrylate and a n-butyl acrylate,

wherein a mass ratio between two (meth)acrylic acid esters having the highest mass proportion among the at least two (meth)acrylic acid esters contained in the (meth)acrylic acid ester-based resin as the polymerization components is 80:20 to 20:80.

2. The pressure-responsive particles according to claim 1 ,

wherein the ratio of the surface coating rate Cs2 to the surface coating rate Cs1 satisfies a relationship of 0.5≤Cs2/Cs1≤0.7.

3. The pressure-responsive particles according to claim 1 ,

wherein the surface coating rate Cs1 is 40% or more and 80% or less, and

the surface coating rate Cs2 is 35% or more and 60% or less.

4. The pressure-responsive particles according to claim 3 ,

wherein the surface coating rate Cs1 is 50% or more and 80% or less, and

the surface coating rate Cs2 is 35% or more and 50% or less.

5. The pressure-responsive particles according to claim 1 ,

wherein an average circularity of the pressure-responsive base particles is 0.955 or more and 0.975 or less.

6. The pressure-responsive particles according to claim 5 ,

wherein the average circularity of the pressure-responsive base particles is 0.955 or more and 0.970 or less.

7. The pressure-responsive particles according to claim 1 ,

wherein a ratio of the surface coating rate Cs2 to a surface coating rate Cs3 by silica particles after application of the following second stress satisfies a relationship of 0.4≤Cs2/Cs3≤0.9,

second stress: 10 g of the pressure-responsive particles are put in a V-shaped mixer with a rotary container having a volume of 0.5 L and rotated at a rotation speed of 40 rpm for 20 minutes at a temperature of 20° C. and a relative humidity of 50%.

8. The pressure-responsive particles according to claim 7 ,

wherein the ratio of the surface coating rate Cs2 to the surface coating rate Cs3 satisfies a relationship of 0.4≤ Cs2/Cs3≤0.8.

9. The pressure-responsive particles according to claim 7 ,

wherein the surface coating rate Cs3 is 40% or more and 60% or less.

10. The pressure-responsive particles according to claim 1 ,

wherein an Al element concentration in a surface layer of the pressure-responsive particles is 0.1 atomic % or more and 1.5 atomic % or less.

11. The pressure-responsive particles according to claim 10 ,

wherein the Al element concentration in the surface layer of the pressure-responsive particles is 0.3 atomic % or more and 0.9 atomic % or less.

12. The pressure-responsive particles according to claim 1 ,

wherein a particle size distribution of the silica particles has peaks in a range of a particle diameter of 100 nm or less and in a range of a particle diameter larger than 100 nm.

13. The pressure-responsive particles according to claim 1 ,

wherein a ratio of a mass Ms2 of the silica particles having a particle diameter larger than 100 nm determined from a particle size distribution of the silica particles to a mass Ms1 of the silica particles having a particle diameter of 100 nm or less determined from a particle size distribution of the silica particles satisfies a relationship of 0.5≤Ms2/Ms1≤1.3.

14. The pressure-responsive particles according to claim 1 ,

wherein the pressure-responsive base particles have a sea phase containing the styrene-based resin and island phases that are dispersed in the sea phase and contain the (meth)acrylic acid ester-based resin.

15. The pressure-responsive particles according to claim 14 ,

wherein an average diameter of the island phases is 200 nm or more and 500 nm or less.

16. The pressure-responsive particles according to claim 1 ,

wherein the pressure-responsive base particles have a core portion that contains the styrene-based resin and the (meth)acrylic acid ester-based resin and a shell layer that coats the core portion.

17. The pressure-responsive particles according to claim 16 ,

wherein the shell layer contains the styrene-based resin.

18. A cartridge that accommodates the pressure-responsive particles according to claim 1 and is attached to and detached from an apparatus for manufacturing a printed matter.

19. An apparatus for manufacturing a printed matter, comprising:

an arrangement unit that accommodates the pressure-responsive particles according to claim 1 and arranges the pressure-responsive particles on a recording medium; and

a crimping unit that folds and crimps the recording medium or stacks and crimps the recording medium and another recording medium together.

20. The apparatus for manufacturing a printed matter according to claim 19 , further comprising:

a color image forming unit that forms a color image on the recording medium by using a coloring material.